diff --git a/.ccls b/.ccls
index a91784d..68cd814 100644
--- a/.ccls
+++ b/.ccls
@@ -1,8 +1,6 @@
-clangd
+clang++
 -std=c++17
 -DDEBUG
--Wall
--Wconversion
 -Iinclude
 -I/usr/include/freetype2
 -I/usr/include/libpng16
diff --git a/.clang-format b/.clang-format
index 3efd2bd..f54912e 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,5 +1,5 @@
 BasedOnStyle: Microsoft
-AccessModifierOffset: -4
+AccessModifierOffset: -3
 AlignAfterOpenBracket: AlwaysBreak
 AlignConsecutiveAssignments: None
 AlignConsecutiveBitFields: None
@@ -21,7 +21,7 @@ AllowShortLoopsOnASingleLine: true
 AlwaysBreakAfterReturnType: None
 AlwaysBreakBeforeMultilineStrings: false
 AlwaysBreakTemplateDeclarations: No
-AttributeMacros: ['__unused']
+AttributeMacros: ['__ununsed']
 BinPackArguments: true
 BinPackParameters: true
 BitFieldColonSpacing: Both
@@ -50,13 +50,12 @@ BreakBeforeTernaryOperators: true
 BreakConstructorInitializers: AfterColon
 BreakInheritanceList: AfterColon
 BreakStringLiterals: true
-ColumnLimit: 120
+ColumnLimit: 140
 CompactNamespaces: false
 ConstructorInitializerAllOnOneLineOrOnePerLine: false
 Cpp11BracedListStyle: true
 DeriveLineEnding: true
 DerivePointerAlignment: false
-EmptyLineAfterAccessModifier: Never
 EmptyLineBeforeAccessModifier: LogicalBlock
 FixNamespaceComments: true
 IncludeBlocks: Regroup
@@ -79,14 +78,13 @@ IncludeCategories:
   - Regex: '^"'
     Priority: 4
     SortPriority: 4
-IndentAccessModifiers: false
 IndentCaseBlocks: true
 IndentCaseLabels: true
 IndentExternBlock: NoIndent
 IndentGotoLabels: false
 IndentPPDirectives: BeforeHash
 IndentRequires: true
-IndentWidth: 4
+IndentWidth: 3
 IndentWrappedFunctionNames: false
 InsertTrailingCommas: None
 KeepEmptyLinesAtTheStartOfBlocks: false
@@ -118,6 +116,6 @@ SpacesInContainerLiterals: false
 SpacesInParentheses: false
 SpacesInSquareBrackets: false
 Standard: c++17
-TabWidth: 4
+TabWidth: 3
 UseCRLF: false
-UseTab: Always
+UseTab: Always
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 68174dc..f6d5daf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,5 @@
 .#.*
 *.kdev4
-*.ttf
 
 .ccls-cache
 .kdev4
diff --git a/README.md b/README.md
deleted file mode 100644
index f3cd877..0000000
--- a/README.md
+++ /dev/null
@@ -1,3 +0,0 @@
-# UUI
-
-Simple and efficient C++ GUI toolkit
diff --git a/ROADMAP.md b/ROADMAP.md
deleted file mode 100644
index b85818b..0000000
--- a/ROADMAP.md
+++ /dev/null
@@ -1,21 +0,0 @@
-* button
-
-* scroll
-
-* Text wrap
-
-* Style
-
-* Text Edition
-
-* projected vertex/raw vertex mode (projection on GPU)
-
-* negative absolute position (from right/bottom)
-
-* VAO/VBO in windows (batched)
-
-* pool/wait mode mechanism
-
-* better font rendering : signed distance
-
-* Rich text component : parsing html? making list of struct of texts (with style information for the rendering)
diff --git a/include/uui/opengl/graphic_context.hpp b/include/graphic_context.hpp
similarity index 65%
rename from include/uui/opengl/graphic_context.hpp
rename to include/graphic_context.hpp
index 037f696..800a70d 100644
--- a/include/uui/opengl/graphic_context.hpp
+++ b/include/graphic_context.hpp
@@ -1,9 +1,8 @@
 #pragma once
 
 // clang-format off
-#define GLAD_GL_IMPLEMENTATION
 #include "glad/glad.h"
-#define GLFW_INCLUDE_NONE
+#define GLFW_INCLUDE_VULKAN
 #include <GLFW/glfw3.h>
 
 #define GLM_FORCE_RADIANS
@@ -12,8 +11,3 @@
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
 // clang-format off
-
-namespace GlConfig
-{
-	constexpr unsigned int FONT_TEXTURE_UNIT = GL_TEXTURE0;
-}
diff --git a/include/uui/application.hpp b/include/uui/application.hpp
index 7d813a0..151ca36 100644
--- a/include/uui/application.hpp
+++ b/include/uui/application.hpp
@@ -3,39 +3,17 @@
 #include <memory>
 #include <string>
 
-#include "uui/types.hpp"
+#include "window.hpp"
 
 namespace uui
 {
-class Window;
 class Application
 {
 public:
-#ifdef DEBUG
-	constexpr static bool debug_mode = true;
-#else
-	constexpr static bool debug_mode = false;
-#endif
-	enum Implementaion
-	{
-		OPENGL
-	};
-
 	virtual void run() = 0;
-	virtual void create_window(int width, int height, const std::string& title, InitFunction<Window> init) = 0;
-	virtual std::shared_ptr<Window> get_window(std::size_t index [[maybe_unused]]) const = 0;
-	virtual ~Application() {};
+	// virtual std::weak_ptr<Window> add_window(int width, int height, const std::string& title) = 0;
 
 protected:
-	static std::shared_ptr<Application> current_application;
-
-	bool initialized;
-
-	virtual void init() = 0;
-	virtual void deinit() = 0;
-
-	friend std::shared_ptr<Application> create_application(Application::Implementaion implementation);
+	static bool application_created;
 };
-
-std::shared_ptr<Application> create_application(Application::Implementaion implementation);
 } // namespace uui
diff --git a/include/uui/component.hpp b/include/uui/component.hpp
index ef91c34..7e41fc9 100644
--- a/include/uui/component.hpp
+++ b/include/uui/component.hpp
@@ -1,45 +1,31 @@
 #pragma once
 
 #include <array>
-#include <memory>
-
-#include "uui/types.hpp"
-#include "uui/window.hpp"
+#include <variant>
 
 namespace uui
 {
-class Container;
 class Component
 {
 public:
-	virtual void set_background_color(float r, float g, float b, float a = 1.0f) = 0;
-
-	ComponentType type() { return _type; }
-	uui::position_t x() { return _position_x; }
-	uui::position_t y() { return _position_y; }
-	uui::size_t width() { return _width; }
-	uui::size_t height() { return _height; }
-
-protected:
-	ComponentType _type = ComponentType::UNASSIGNED;
-
-	std::shared_ptr<Window> _window;
-	std::size_t _window_index;
-	std::shared_ptr<Container> _parent;
-	std::size_t _parent_index;
-
-	uui::position_t _position_x;
-	uui::position_t _position_y;
-	uui::size_t _width;
-	uui::size_t _height;
-
-	bool _coord_all_relative;
-
-	std::array<float, 4> _background_color;
-
-	bool _initialized = false;
+	Component(
+		 const std::variant<int, float> x, const std::variant<int, float> y, const std::variant<int, float> width,
+		 const std::variant<int, float> height):
+		 position_x(x),
+		 position_y(y), size_width(width), size_height(height)
+	{
+		background_color = {0.0f, 0.0f, 0.0f, 0.0f};
+	}
 
 	virtual void render() = 0;
+
+protected:
+	std::variant<int, float> position_x;
+	std::variant<int, float> position_y;
+	std::variant<int, float> size_width;
+	std::variant<int, float> size_height;
+
+	std::array<float, 4> background_color;
 };
 
 } // namespace uui
diff --git a/include/uui/config.hpp b/include/uui/config.hpp
new file mode 100644
index 0000000..1afb3a0
--- /dev/null
+++ b/include/uui/config.hpp
@@ -0,0 +1,8 @@
+#pragma once
+
+#include "graphic_context.hpp"
+
+namespace Config
+{
+constexpr unsigned int FONT_TEXTURE_UNIT = GL_TEXTURE0;
+}
diff --git a/include/uui/container.hpp b/include/uui/container.hpp
deleted file mode 100644
index 782ff97..0000000
--- a/include/uui/container.hpp
+++ /dev/null
@@ -1,12 +0,0 @@
-#pragma once
-
-#include "uui/component.hpp"
-#include "uui/container_interface.hpp"
-#include "uui/types.hpp"
-
-namespace uui
-{
-class Container: virtual public Component, virtual public ContainerInterface
-{};
-
-} // namespace uui
diff --git a/include/uui/container_interface.hpp b/include/uui/container_interface.hpp
deleted file mode 100644
index e43f496..0000000
--- a/include/uui/container_interface.hpp
+++ /dev/null
@@ -1,22 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <tuple>
-
-#include "uui/types.hpp"
-
-namespace uui
-{
-class Component;
-class ContainerInterface
-{
-public:
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index [[maybe_unused]]) const = 0;
-
-protected:
-	virtual std::size_t push_child(std::shared_ptr<Component> child) = 0;
-	virtual std::shared_ptr<Component> get_child(std::size_t index) const = 0;
-	virtual void remove_child(std::size_t index) = 0;
-};
-
-} // namespace uui
diff --git a/include/uui/flex.hpp b/include/uui/flex.hpp
deleted file mode 100644
index 1adf974..0000000
--- a/include/uui/flex.hpp
+++ /dev/null
@@ -1,16 +0,0 @@
-#pragma once
-
-#include <string>
-#include <tuple>
-
-#include "uui/stack.hpp"
-
-namespace uui
-{
-class Flex: virtual public Stack
-{
-protected:
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index) const = 0;
-};
-
-} // namespace uui
diff --git a/include/uui/font_manager.hpp b/include/uui/font_manager.hpp
deleted file mode 100644
index 52da172..0000000
--- a/include/uui/font_manager.hpp
+++ /dev/null
@@ -1,56 +0,0 @@
-#pragma once
-
-#include <string>
-#include <tuple>
-#include <vector>
-
-#include <ft2build.h>
-#include FT_FREETYPE_H
-
-namespace uui
-{
-class Window;
-class FontManager
-{
-	friend class Window;
-
-public:
-	struct character_info
-	{
-		float advance_x; // advance.x
-		float advance_y; // advance.y
-
-		float bitmap_width; // bitmap.width;
-		float bitmap_height; // bitmap.rows;
-
-		float bitmap_left; // bitmap_left;
-		float bitmap_top; // bitmap_top;
-
-		float texture_x; // x offset of glyph in texture coordinates
-		float texture_y; // y offset of glyph in texture coordinates
-	};
-
-	struct Font
-	{
-		character_info char_infos[256];
-		unsigned int atlas_texture;
-		unsigned int atlas_width;
-		unsigned int atlas_height;
-	};
-
-	std::vector<Font> fonts;
-
-	virtual void render_text(
-		const std::string& text, Font& font, float x, float y, float scale_x, float scale_y,
-		const std::tuple<float, float, float, float>& text_color) = 0;
-	virtual std::tuple<int, int> get_text_size(const std::string& text, Font& font, float scale_x, float scale_y) = 0;
-
-protected:
-	static constexpr int ATLAS_MAX_WIDTH = 1024;
-
-	bool initialized;
-
-	FT_Library ft;
-	virtual const Font& init_font(const std::string& font_path, unsigned int font_size) = 0;
-};
-} // namespace uui
diff --git a/include/uui/label.hpp b/include/uui/label.hpp
deleted file mode 100644
index 2de7c22..0000000
--- a/include/uui/label.hpp
+++ /dev/null
@@ -1,22 +0,0 @@
-#pragma once
-
-#include <string>
-#include <tuple>
-
-#include "uui/component.hpp"
-
-namespace uui
-{
-class Label: virtual public Component
-{
-protected:
-	std::size_t font_index;
-
-	std::string text;
-	std::tuple<float, float, float, float> text_color;
-
-	int text_width;
-	int text_height;
-};
-
-} // namespace uui
diff --git a/include/uui/opengl/application.hpp b/include/uui/opengl/application.hpp
index 4d2d4e6..df15fe4 100644
--- a/include/uui/opengl/application.hpp
+++ b/include/uui/opengl/application.hpp
@@ -2,32 +2,89 @@
 
 #include <memory>
 #include <string>
+#include <variant>
 #include <vector>
 
 #include "graphic_context.hpp"
-#include "uui/application.hpp"
-#include "uui/types.hpp"
+#include "uui/opengl/font_manager.hpp"
 
 namespace uui
 {
 class GlWindow;
-class GlApplication final: virtual public Application
+class GlApplication
 {
 	friend class GlWindow;
 
 public:
+#ifdef DEBUG
+	constexpr static bool debug_mode = true;
+#else
+	constexpr static bool debug_mode = false;
+#endif
 	std::vector<std::shared_ptr<GlWindow>> windows;
 
 	GlApplication();
-	virtual ~GlApplication() final;
+	~GlApplication();
 
-	void run() final;
-	void create_window(int width, int height, const std::string& title, InitFunction<Window> init) final;
-	std::shared_ptr<Window> get_window(std::size_t index) const final;
+	void run();
+	std::shared_ptr<GlWindow> create_window(int width, int height, const std::string& title);
+	std::shared_ptr<GlWindow> get_window(size_t index) const;
+
+private:
+	static GlApplication* application_pointer;
+};
+
+class GlLabel;
+class GlComponent;
+class GlWindow
+{
+	friend class GlApplication;
+	friend class GlComponent;
+	friend class GlLabel;
+
+public:
+	std::string title;
+	std::vector<std::shared_ptr<GlComponent>> components;
+
+	GlWindow(const GlWindow&) = delete;
+	GlWindow(GlWindow&&) = delete;
+	~GlWindow();
+
+	std::shared_ptr<GlComponent> create_component(
+		 const std::variant<int, float> x, const std::variant<int, float> y, const std::variant<int, float> width,
+		 const std::variant<int, float> height);
+	std::shared_ptr<GlLabel> create_label(
+		 const std::variant<int, float> x, const std::variant<int, float> y, const std::string& text,
+		 const std::tuple<float, float, float, float>& text_color);
 
 protected:
-	void init() final;
-	void deinit() final;
+	GlApplication* app;
+
+	GlFontManager font_manager;
+
+	int width;
+	int height;
+	bool render_needed;
+	bool resize_needed;
+
+	bool iconified;
+
+	size_t index;
+	bool initialized;
+
+	GLFWwindow* glfw_window;
+
+	GLuint gl_program;
+
+	GlWindow(GlApplication* app, size_t index, int width, int height, const std::string& title);
+
+	void init();
+	void deinit();
+	void render();
+
+	static void glfw_resize_callback(GLFWwindow* window, int width, int height);
+	static void glfw_iconify_callback(GLFWwindow* window, int iconified);
+	static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);
 };
 
 } // namespace uui
diff --git a/include/uui/opengl/button.hpp b/include/uui/opengl/button.hpp
deleted file mode 100644
index 0df1ff2..0000000
--- a/include/uui/opengl/button.hpp
+++ /dev/null
@@ -1,27 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <string>
-#include <tuple>
-
-#include "uui/opengl/component.hpp"
-
-namespace uui
-{
-class GlButton: public GlComponent
-{
-	friend class GlWindow;
-
-protected:
-	GlButton(
-		std::shared_ptr<GlWindow> window, std::size_t window_index, std::shared_ptr<GlContainer> parent,
-		std::size_t parent_index, const position_t x, const position_t y, const Direction direction);
-	GlButton(
-		std::shared_ptr<GlWindow> window, std::size_t window_index, const position_t x, const position_t y,
-		const Direction direction): GlButton(window, window_index, window, window_index, x, y, direction)
-	{}
-
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index) const;
-};
-
-} // namespace uui
diff --git a/include/uui/opengl/component.hpp b/include/uui/opengl/component.hpp
index 6ecaa99..b2c57bc 100644
--- a/include/uui/opengl/component.hpp
+++ b/include/uui/opengl/component.hpp
@@ -2,50 +2,49 @@
 
 #include <array>
 #include <memory>
+#include <variant>
 
-#include "uui/component.hpp"
-#include "uui/opengl/graphic_context.hpp"
-#include "uui/opengl/window.hpp"
-#include "uui/types.hpp"
+#include "graphic_context.hpp"
+#include "window.hpp"
 
 namespace uui
 {
-class GlContainer;
-class GlFlex;
-class GlStack;
-class GlComponent: public std::enable_shared_from_this<GlComponent>, virtual public Component
+class GlComponent
 {
-	friend class GlContainer;
 	friend class GlWindow;
-	friend class GlFlex;
-	friend class GlStack;
 
 public:
-	virtual ~GlComponent();
+	GlComponent(const GlComponent&) = delete;
+	GlComponent(GlComponent&&) = delete;
+	~GlComponent();
 
-	void set_background_color(float r, float g, float b, float a = 1.0f) final;
+	void set_background_color(float r, float g, float b, float a = 1.0f);
 
 protected:
-	std::shared_ptr<GlWindow> gl_window;
+	std::shared_ptr<GlWindow> window;
+
+	std::variant<int, float> position_x;
+	std::variant<int, float> position_y;
+	std::variant<int, float> size_width;
+	std::variant<int, float> size_height;
+	bool coord_all_relative;
+
+	std::array<float, 4> background_color;
+
+	bool initialized;
+
 	GLuint gl_vbo;
 	GLuint gl_vao;
 	GLuint gl_ebo;
 
 	GlComponent(
-		std::shared_ptr<GlWindow> window, std::size_t window_index, std::shared_ptr<GlContainer> parent,
-		std::size_t parent_index, const ComponentParams& params);
-	GlComponent(std::shared_ptr<GlWindow> window, std::size_t window_index, const ComponentParams& params):
-		GlComponent(window, window_index, nullptr, 0, params)
-	{}
-	GlComponent(const GlComponent&) = delete;
-	GlComponent(GlComponent&&) = default;
-	std::shared_ptr<GlComponent> getptr() { return shared_from_this(); }
-
-	virtual void render();
+		 std::shared_ptr<GlWindow> window, const std::variant<int, float> x, const std::variant<int, float> y,
+		 const std::variant<int, float> width, const std::variant<int, float> height);
 
 	virtual void init();
 	virtual void set_vbo_data();
 	virtual void deinit();
+	virtual void render();
 	virtual void on_resize();
 };
 
diff --git a/include/uui/opengl/container.hpp b/include/uui/opengl/container.hpp
deleted file mode 100644
index 8deaf6d..0000000
--- a/include/uui/opengl/container.hpp
+++ /dev/null
@@ -1,18 +0,0 @@
-#pragma once
-
-#include <cstdlib>
-
-#include <iostream>
-#include <memory>
-#include <vector>
-
-#include "uui/container.hpp"
-#include "uui/opengl/component.hpp"
-#include "uui/opengl/container_interface.hpp"
-
-namespace uui
-{
-class GlContainer: virtual public Container, virtual public GlContainerInterface
-{};
-
-} // namespace uui
diff --git a/include/uui/opengl/container_interface.hpp b/include/uui/opengl/container_interface.hpp
deleted file mode 100644
index e068ffa..0000000
--- a/include/uui/opengl/container_interface.hpp
+++ /dev/null
@@ -1,28 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <tuple>
-
-#include "uui/component.hpp"
-#include "uui/container_interface.hpp"
-#include "uui/types.hpp"
-
-namespace uui
-{
-class GlComponent;
-class GlContainerInterface: virtual public ContainerInterface
-{
-public:
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index [[maybe_unused]]) const override;
-
-protected:
-	virtual std::size_t push_child(std::shared_ptr<Component> child) final;
-	std::size_t push_child(std::shared_ptr<GlComponent> child);
-	virtual std::shared_ptr<Component> get_child(std::size_t index) const final;
-	virtual void remove_child(std::size_t index) final;
-
-	virtual ~GlContainerInterface();
-
-	std::vector<std::shared_ptr<GlComponent>> components;
-};
-} // namespace uui
diff --git a/include/uui/opengl/flex.hpp b/include/uui/opengl/flex.hpp
deleted file mode 100644
index 975d30c..0000000
--- a/include/uui/opengl/flex.hpp
+++ /dev/null
@@ -1,29 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <string>
-#include <tuple>
-
-#include "uui/flex.hpp"
-#include "uui/opengl/container.hpp"
-#include "uui/opengl/stack.hpp"
-#include "uui/opengl/window.hpp"
-
-namespace uui
-{
-class GlFlex: virtual public GlStack, virtual public Flex
-{
-	friend class GlWindow;
-
-protected:
-	GlFlex(
-		std::shared_ptr<GlWindow> window, std::size_t window_index, std::shared_ptr<GlContainer> parent,
-		std::size_t parent_index, const StackParams& params);
-	GlFlex(std::shared_ptr<GlWindow> window, std::size_t window_index, const StackParams& params):
-		GlFlex(window, window_index, nullptr, 0, params)
-	{}
-
-	std::tuple<int, int> get_child_position(const std::size_t child_index) const override;
-};
-
-} // namespace uui
diff --git a/include/uui/opengl/font_manager.hpp b/include/uui/opengl/font_manager.hpp
index e797f1b..07184a5 100644
--- a/include/uui/opengl/font_manager.hpp
+++ b/include/uui/opengl/font_manager.hpp
@@ -5,32 +5,64 @@
 #include <tuple>
 #include <vector>
 
-#include "uui/font_manager.hpp"
-#include "uui/opengl/graphic_context.hpp"
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include "graphic_context.hpp"
 
 namespace uui
 {
 class GlWindow;
-class GlFontManager final: public FontManager
+class GlFontManager
 {
 	friend class GlWindow;
 
 public:
+	struct character_info
+	{
+		float advance_x; // advance.x
+		float advance_y; // advance.y
+
+		float bitmap_width; // bitmap.width;
+		float bitmap_height; // bitmap.rows;
+
+		float bitmap_left; // bitmap_left;
+		float bitmap_top; // bitmap_top;
+
+		float texture_x; // x offset of glyph in texture coordinates
+		float texture_y; // y offset of glyph in texture coordinates
+	};
+
+	struct Font
+	{
+		character_info char_infos[256];
+		GLuint atlas_texture;
+		unsigned int atlas_width;
+		unsigned int atlas_height;
+	};
+
+	std::vector<Font> fonts;
+
 	GlFontManager();
 	~GlFontManager();
 
 	void render_text(
-		const std::string& text, Font& font, float x, float y, float scale_x, float scale_y,
-		const std::tuple<float, float, float, float>& text_color) final;
-	std::tuple<int, int> get_text_size(const std::string& text, Font& font, float scale_x, float scale_y) final;
+		 const std::string& text, Font& font, float x, float y, float scale_x, float scale_y,
+		 const std::tuple<float, float, float, float>& text_color);
+	std::tuple<int, int> get_text_size(const std::string& text, Font& font, float scale_x, float scale_y);
 
 private:
+	static constexpr int ATLAS_MAX_WIDTH = 1024;
+
+	bool initialized;
+
+	FT_Library ft;
+
 	GLuint gl_program;
 	GLuint gl_vao;
 	GLuint gl_vbo;
 
 	void init();
 	void deinit();
-	const Font& init_font(const std::string& font_path, unsigned int font_size);
+	const Font& init_font(const std::string& font_path, size_t font_size);
 };
 } // namespace uui
diff --git a/include/uui/opengl/label.hpp b/include/uui/opengl/label.hpp
index 266b615..fcb1d24 100644
--- a/include/uui/opengl/label.hpp
+++ b/include/uui/opengl/label.hpp
@@ -3,20 +3,18 @@
 #include <string>
 #include <tuple>
 
-#include "uui/label.hpp"
 #include "uui/opengl/component.hpp"
-#include "uui/opengl/container.hpp"
-#include "uui/opengl/window.hpp"
 
 namespace uui
 {
-class GlFlex;
-class GlStack;
-class GlLabel final: virtual public GlComponent, virtual public Label
+class GlLabel: public GlComponent
 {
 	friend class GlWindow;
-	friend class GlFlex;
-	friend class GlStack;
+
+	size_t font_index;
+
+	float get_width() const;
+	float get_height() const;
 
 protected:
 	std::string text;
@@ -26,13 +24,10 @@ protected:
 	int text_height;
 
 	GlLabel(
-		std::shared_ptr<GlWindow> window, std::size_t window_index, std::shared_ptr<GlContainer> parent,
-		std::size_t parent_index, const LabelParams& params);
-	GlLabel(std::shared_ptr<GlWindow> window, std::size_t window_index, const LabelParams& params):
-		GlLabel(window, window_index, nullptr, 0, params)
-	{}
+		 std::shared_ptr<GlWindow> window, const std::variant<int, float> x, const std::variant<int, float> y, const std::string& text,
+		 const std::tuple<float, float, float, float>& text_color);
 
-	void render() final;
+	void render();
 };
 
 } // namespace uui
diff --git a/include/uui/opengl/stack.hpp b/include/uui/opengl/stack.hpp
deleted file mode 100644
index 52310c4..0000000
--- a/include/uui/opengl/stack.hpp
+++ /dev/null
@@ -1,32 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <string>
-#include <tuple>
-
-#include "uui/opengl/component.hpp"
-#include "uui/opengl/container.hpp"
-#include "uui/stack.hpp"
-
-namespace uui
-{
-class GlStack: virtual public GlComponent, virtual public GlContainer, virtual public Stack
-{
-	friend class GlWindow;
-
-public:
-	void create_component(const StackComponentParams& params, InitFunction<Component> init) override;
-	void create_label(const StackLabelParams& params, InitFunction<Label> init) override;
-
-protected:
-	GlStack(
-		std::shared_ptr<GlWindow> window, std::size_t window_index, std::shared_ptr<GlContainer> parent,
-		std::size_t parent_index, const StackParams& params);
-	GlStack(std::shared_ptr<GlWindow> window, std::size_t window_index, const StackParams& params):
-		GlStack(window, window_index, nullptr, 0, params)
-	{}
-
-	std::tuple<int, int> get_child_position(const std::size_t child_index) const override;
-};
-
-} // namespace uui
diff --git a/include/uui/opengl/window.hpp b/include/uui/opengl/window.hpp
index 6a5ab32..dd3f0d0 100644
--- a/include/uui/opengl/window.hpp
+++ b/include/uui/opengl/window.hpp
@@ -1,56 +1,3 @@
 #pragma once
 
 #include "uui/opengl/application.hpp"
-#include "uui/opengl/container_interface.hpp"
-#include "uui/opengl/font_manager.hpp"
-#include "uui/types.hpp"
-#include "uui/window.hpp"
-
-namespace uui
-{
-class GlComponent;
-class GlContainer;
-class GlFlex;
-class GlLabel;
-class GlStack;
-class GlWindow:
-	public std::enable_shared_from_this<GlWindow>,
-	virtual public Window,
-	virtual public GlContainerInterface
-{
-	friend class GlApplication;
-	friend class GlComponent;
-	friend class GlFlex;
-	friend class GlLabel;
-	friend class GlStack;
-
-public:
-	GlWindow(const GlWindow&) = delete;
-	GlWindow(GlWindow&&) = delete;
-	~GlWindow();
-
-	void create_component(const ComponentParams& params, InitFunction<Component> init) final;
-	void create_label(const LabelParams& params, InitFunction<Label> init) final;
-	void create_flex(const StackParams& params, InitFunction<Flex> init) final;
-	void create_stack(const StackParams& params, InitFunction<Stack> init) final;
-
-protected:
-	void render() final;
-
-	std::shared_ptr<GlFontManager> gl_font_manager;
-
-	GLFWwindow* glfw_window;
-	GLuint gl_program;
-
-	GlWindow(std::shared_ptr<Application> app, int width, int height, const std::string& title);
-	std::shared_ptr<GlWindow> getptr() { return shared_from_this(); }
-
-	void init();
-	void deinit();
-
-	static void glfw_resize_callback(GLFWwindow* window, int width, int height);
-	static void glfw_iconify_callback(GLFWwindow* window, int iconified);
-	static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);
-	// static void glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods);
-};
-} // namespace uui
diff --git a/include/uui/stack.hpp b/include/uui/stack.hpp
deleted file mode 100644
index df89240..0000000
--- a/include/uui/stack.hpp
+++ /dev/null
@@ -1,25 +0,0 @@
-#pragma once
-
-#include <string>
-#include <tuple>
-
-#include "uui/component.hpp"
-#include "uui/label.hpp"
-
-namespace uui
-{
-class Stack: virtual public Component
-{
-public:
-	virtual void create_component(const StackComponentParams& params, InitFunction<Component> init) = 0;
-	virtual void create_label(const StackLabelParams& params, InitFunction<Label> init) = 0;
-
-protected:
-	Direction direction;
-	int content_width;
-	int content_height;
-
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index) const = 0;
-};
-
-} // namespace uui
diff --git a/include/uui/style.hpp b/include/uui/style.hpp
deleted file mode 100644
index c3d4781..0000000
--- a/include/uui/style.hpp
+++ /dev/null
@@ -1,46 +0,0 @@
-#pragma once
-
-#include <memory>
-#include <optional>
-#include <tuple>
-
-#include "types.hpp"
-
-namespace uui
-{
-struct Style
-{
-	enum Position
-	{
-		RELATIVE,
-		ABSOLUTE
-	};
-	enum Alignment
-	{
-		START,
-		CENTER,
-		END
-	};
-	struct AbsolutePostion
-	{
-		std::optional<position_t> left;
-		std::optional<position_t> right;
-		std::optional<position_t> top;
-		std::optional<position_t> bottom;
-	};
-
-	// Layout
-	Position position;
-	Alignment horizontal_alignment;
-	Alignment vertical_alignment;
-	std::optional<uui::size_t> width;
-	std::optional<uui::size_t> height;
-	std::optional<uui::size_t> margin;
-	std::optional<uui::size_t> padding;
-	// For absolute positioning
-	std::unique_ptr<AbsolutePostion> absolute_position;
-
-	// Color
-	std::optional<std::tuple<float, float, float, float>> background_color;
-};
-} // namespace uui
diff --git a/include/uui/types.hpp b/include/uui/types.hpp
deleted file mode 100644
index d329768..0000000
--- a/include/uui/types.hpp
+++ /dev/null
@@ -1,67 +0,0 @@
-#pragma once
-
-#include <functional>
-#include <tuple>
-#include <variant>
-
-namespace uui
-{
-namespace Config
-{
-constexpr int MOUSE_GRID_WIDTH = 20;
-constexpr int MOUSE_GRID_HEIGHT = 20;
-}; // namespace Config
-
-template<typename T> using InitFunction = const std::function<void(T&)>&;
-typedef std::variant<int, float> position_t;
-typedef std::variant<int, float> size_t;
-typedef std::tuple<float, float, float, float> color_t;
-
-enum class ComponentType
-{
-	UNASSIGNED,
-	COMPONENT,
-	LABEL,
-	FLEX,
-	STACK,
-	WINDOW
-};
-
-enum class Direction
-{
-	HORIZONTAL,
-	VERTICAL
-};
-
-struct ComponentParams
-{
-	uui::position_t x;
-	uui::position_t y;
-	uui::size_t width;
-	uui::size_t height;
-};
-struct LabelParams
-{
-	uui::position_t x;
-	uui::position_t y;
-	const std::string& text;
-	const uui::color_t& text_color;
-};
-struct StackParams
-{
-	const uui::position_t x;
-	const uui::position_t y;
-	const uui::Direction direction;
-};
-struct StackComponentParams
-{
-	uui::size_t width;
-	uui::size_t height;
-};
-struct StackLabelParams
-{
-	const std::string& text;
-	const uui::color_t& text_color;
-};
-
-} // namespace uui
diff --git a/include/uui/uui.hpp b/include/uui/uui.hpp
deleted file mode 100644
index 6718260..0000000
--- a/include/uui/uui.hpp
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-#include "uui/application.hpp"
-#include "uui/component.hpp"
-#include "uui/flex.hpp"
-#include "uui/label.hpp"
-#include "uui/stack.hpp"
-#include "uui/types.hpp"
-#include "uui/window.hpp"
diff --git a/include/uui/window.hpp b/include/uui/window.hpp
index 16abe65..b5d6c49 100644
--- a/include/uui/window.hpp
+++ b/include/uui/window.hpp
@@ -1,52 +1,24 @@
 #pragma once
 
-#include <array>
 #include <memory>
 #include <string>
+#include <vector>
 
-#include "uui/application.hpp"
-#include "uui/container_interface.hpp"
-#include "uui/font_manager.hpp"
-#include "uui/types.hpp"
+#include "graphic_context.hpp"
+#include "uui/component.hpp"
 
 namespace uui
 {
-class Component;
-class Label;
-class Flex;
-class Stack;
-class Window: virtual public ContainerInterface
+class Window
 {
-	friend class Component;
-
 public:
-	std::shared_ptr<FontManager> font_manager;
+	std::string title;
 
-	virtual void create_component(const ComponentParams& params, InitFunction<Component> init) = 0;
-	virtual void create_label(const LabelParams& params, InitFunction<Label> init) = 0;
-	virtual void create_flex(const StackParams& params, InitFunction<Flex> init) = 0;
-	virtual void create_stack(const StackParams& params, InitFunction<Stack> init) = 0;
-
-	const std::string& title() { return _title; }
-	int width() { return _width; };
-	int height() { return _height; };
+	virtual void add_component(const Component& box) = 0;
 
 protected:
-	ComponentType _type = ComponentType::UNASSIGNED;
+	GLFWwindow* glfw_window;
 
-	std::shared_ptr<Application> _app;
-	bool _initialized;
-
-	std::string _title;
-	int _width;
-	int _height;
-	bool _render_needed;
-	bool _resize_needed;
-	bool _iconified;
-
-	std::array<std::array<std::vector<std::shared_ptr<Component>>, Config::MOUSE_GRID_HEIGHT>, Config::MOUSE_GRID_WIDTH>
-		_grid_click;
-
-	virtual void render() = 0;
+	virtual void draw() = 0;
 };
 } // namespace uui
diff --git a/make.py b/make.py
index b3b24ce..7799daf 100644
--- a/make.py
+++ b/make.py
@@ -1,38 +1,50 @@
 #! python3
 
+import os
 from pathlib import Path
 import shutil
 
-from umake.umake import get_hash, make, Config
+from umake import get_hash, make
+
+
+class Config:
+    CC = 'g++'
+    APPS = ['test/example_gl', 'test/benchmark_text']
+    IGNORE_APPS = []
+    JOB_COUNT = int(os.cpu_count() * 0.8)
+
+    BIN_DIR = Path('bin')
+    INCLUDE_DIR = Path('include')
+    OBJECT_DIR = Path('obj')
+    SOURCE_DIR = Path('src')
+
+    COMMON_FLAGS = '-std=c++17 -fno-semantic-interposition'
+    COMMON_DEBUG_FLAGS = '-g -DDEBUG'
+    COMMON_RELEASE_FLAGS = '-O2 -flto'
+    COMPILE_FLAGS = f'-Wall -I{INCLUDE_DIR} `pkg-config --cflags glfw3 vulkan gl x11 freetype2`'
+    LINK_FLAGS = '-lpthread -ldl `pkg-config --libs glfw3 vulkan gl x11 freetype2`'
+
+    PRE_COMPILE_FUNCTION = None
+
+    CPP_SOURCES = [filepath for filepath in SOURCE_DIR.rglob('*.cpp') if not filepath.name.startswith('.')]
 
 
 def main():
-    config = Config()
-
     def pre_compile():
         # Copying OpenGL shaders
-        src_opengl_shader_path = config.source_dir / 'uui' / 'opengl' / 'shaders'
+        src_opengl_shader_path = Config.SOURCE_DIR / 'uui' / 'opengl' / 'shaders'
         for shader_path in (
                 list(src_opengl_shader_path.rglob('*.vert'))
                 + list(src_opengl_shader_path.rglob('*.frag'))):
-            out_path = config.bin_dir / shader_path.relative_to(config.source_dir)
+            out_path = Config.BIN_DIR / shader_path.relative_to(Config.SOURCE_DIR)
             if out_path.exists() and get_hash(shader_path) == get_hash(out_path):
                 continue
             if not out_path.parent.exists():
                 out_path.parent.mkdir(parents=True)
             shutil.copy(shader_path, out_path)
 
-
-    config.apps = [str(p.relative_to(Path('src')))[:-4] for p in (config.source_dir / 'test').rglob('*.cpp')]
-    config.watch = True
-
-    config.common_flags = '-std=c++20 -fno-semantic-interposition'
-    config.common_debug_flags = '-g -Og -DDEBUG'
-    config.common_release_flags = '-O2 -flto=auto'
-    config.compile_flags = f'-Wall -Wextra -Wpedantic -Wconversion -I{config.include_dir} `pkg-config --cflags glfw3 gl x11 freetype2`'
-    config.link_flags = '-lpthread -ldl `pkg-config --libs glfw3 gl freetype2`'
-    config.pre_compile_function = pre_compile
-    make(config)
+    Config.PRE_COMPILE_FUNCTION = pre_compile
+    make(Config)
 
 
 if __name__ == '__main__':
diff --git a/makefile b/makefile
index dde7e0f..db2db6a 100644
--- a/makefile
+++ b/makefile
@@ -1,7 +1,7 @@
 MAKE_PATH="."
 UMAKE_PATH="umake"
 
-.PHONY: all watch debug debug_watch clean lint
+.PHONY: all clean
 
 all:
 	@PYTHONPATH=$(UMAKE_PATH) python $(MAKE_PATH)/make.py
@@ -11,6 +11,3 @@ debug:
 
 clean:
 	@PYTHONPATH=$(UMAKE_PATH) python $(MAKE_PATH)/make.py --clean
-
-lint:
-	@clang-format --dry-run --Werror include/uui/*.hpp include/uui/**/*.hpp src/uui/*.cpp src/uui/**/*.cpp src/test/*.cpp
diff --git a/manifest.md b/manifest.md
index d817af0..b7f40bd 100644
--- a/manifest.md
+++ b/manifest.md
@@ -1,5 +1,6 @@
 # UUI : micro UI Toolkit
 
+
 * C++ + Vulkan/OpenGL
 
 * Python binding
@@ -8,10 +9,6 @@
 
 * Let custom rendering
 
-* Canvas for easy drawing
-
-* Style/Config watch option : real-time update on file change
-
 
 ## Technical
 
@@ -30,4 +27,4 @@
 
 ## Layout / Style
 
-* CSS subset
+* Constraint based? padding/margin?
diff --git a/src/test/benchmark_text.cpp b/src/test/benchmark_text.cpp
index 9acca2f..d51a978 100644
--- a/src/test/benchmark_text.cpp
+++ b/src/test/benchmark_text.cpp
@@ -1,6 +1,8 @@
 #include <iostream>
 
-#include "uui/uui.hpp"
+#include "uui/opengl/application.hpp"
+#include "uui/opengl/component.hpp"
+#include "uui/opengl/label.hpp"
 
 using namespace std;
 
@@ -8,12 +10,12 @@ int main()
 {
 	try
 	{
-		auto app = uui::create_application(uui::Application::OPENGL);
-		app->create_window(800, 600, "OpenGl!", [](uui::Window& window) {
-			for(int i = 0; i < 100; i += 1)
-				window.create_label({4 * i, 4 * i, "Hello World!", {1.0f, 1.0f, 1.0f, 0.5f}}, nullptr);
-		});
-		app->run();
+		uui::GlApplication app;
+		// uui::GlApplication app2; // exception : application already created
+		auto window = app.create_window(800, 600, "OpenGl!");
+		for(int i = 0; i < 100; i += 1)
+			window->create_label(4*i, 4*i, "Hello World!", {1.0f, 1.0f, 1.0f, 0.5f});
+		app.run();
 	}
 	catch(const std::exception& error)
 	{
diff --git a/src/test/example_gl.cpp b/src/test/example_gl.cpp
index cc50eec..f1eeb8b 100644
--- a/src/test/example_gl.cpp
+++ b/src/test/example_gl.cpp
@@ -1,6 +1,8 @@
 #include <iostream>
 
-#include "uui/uui.hpp"
+#include "uui/opengl/application.hpp"
+#include "uui/opengl/component.hpp"
+#include "uui/opengl/label.hpp"
 
 using namespace std;
 
@@ -10,94 +12,36 @@ int main()
 	{
 		cout << "Starting example 1" << endl;
 		{
-			auto app = uui::create_application(uui::Application::OPENGL);
-			// auto app2 = uui::create_application(uui::Application::OPENGL); // exception : application already created
-			app->create_window(800, 600, "OpenGl!", [](uui::Window& window) {
-				window.create_component({.x = 0, .y = 100, .width = 0.5f, .height = 50}, [](uui::Component& component) {
-					component.set_background_color(0.8f, 0.1f, 0.5f);
-				});
-
-				window.create_component(
-					{.x = 0.25f, .y = 50, .width = 0.4f, .height = 150},
-					[](uui::Component& component) { component.set_background_color(0.3f, 0.8f, 0.4f, 0.5f); });
-
-				window.create_label(
-					{.x = 50, .y = 50, .text = "Hello World!", .text_color = {0.5f, 1.0f, 0.5f, 1.0f}},
-					[](uui::Label& label) { label.set_background_color(0.1f, 0.2f, 0.5f, 0.8f); });
-
-				window.create_label({0.5f, 0.5f, "Hello World!", {1.0f, 1.0f, 1.0f, 0.5f}}, [](uui::Label& label) {
-					label.set_background_color(0.5f, 0.5f, 0.1f);
-				});
-				window.create_label({0.75f, 0.75f, "Hello World!", {1.0f, 1.0f, 1.0f, 0.1f}}, {});
-
-				window.create_flex({200, 0.6f, uui::Direction::HORIZONTAL}, [](uui::Flex& flex) {
-					flex.create_component({.width = 100, .height = 50}, [](uui::Component& component) {
-						component.set_background_color(0.2f, 0.75f, 0.25f);
-					});
-					flex.create_label({.text = "test", .text_color = {0.8f, 0.2f, 0.2f, 1.0f}}, {});
-					flex.create_component({100, 20}, [](uui::Component& component) {
-						component.set_background_color(0.2f, 0.25f, 0.75f);
-					});
-				});
-
-				window.create_flex({50, 400, uui::Direction::VERTICAL}, [](uui::Flex& flex) {
-					flex.create_component({50, 100}, [](uui::Component& component) {
-						component.set_background_color(0.2f, 0.75f, 0.25f);
-					});
-					flex.create_label({"test", {0.8f, 0.2f, 0.2f, 1.0f}}, {});
-					flex.create_component({100, 20}, [](uui::Component& component) {
-						component.set_background_color(0.2f, 0.25f, 0.75f);
-					});
-				});
-			});
-
-			app->create_window(800, 600, "OpenGl 2", [](uui::Window& window) {
-				window.create_stack(
-					{.x = 200, .y = 0.6f, .direction = uui::Direction::HORIZONTAL}, [](uui::Stack& stack) {
-						stack.create_component({.width = 100, .height = 50}, [](uui::Component& component) {
-							component.set_background_color(0.2f, 0.75f, 0.25f);
-						});
-						stack.create_label({.text = "test", .text_color = {0.8f, 0.2f, 0.2f, 1.0f}}, {});
-						stack.create_component({.width = 100, .height = 20}, [](uui::Component& component) {
-							component.set_background_color(0.2f, 0.25f, 0.75f);
-						});
-					});
-
-				window.create_stack({.x = 50, .y = 400, .direction = uui::Direction::VERTICAL}, [](uui::Stack& stack) {
-					stack.create_component({.width = 100, .height = 50}, [](uui::Component& component) {
-						component.set_background_color(0.2f, 0.75f, 0.25f);
-					});
-					stack.create_label({.text = "test", .text_color = {0.8f, 0.2f, 0.2f, 1.0f}}, {});
-					stack.create_component({.width = 100, .height = 20}, [](uui::Component& component) {
-						component.set_background_color(0.2f, 0.25f, 0.75f);
-					});
-				});
-			});
-
-			app->run();
+			uui::GlApplication app;
+			// uui::GlApplication app2; // exception : application already created
+			auto window = app.create_window(800, 600, "OpenGl!");
+			auto comp = window->create_component(0, 100, 0.5f, 50);
+			comp->set_background_color(0.8f, 0.1f, 0.5f);
+			comp = window->create_component(0.25f, 50, 0.4f, 150);
+			comp->set_background_color(0.3f, 0.8f, 0.4f, 0.5f);
+			auto label = window->create_label(50, 50, "Hello World!", {0.5f, 1.0f, 0.5f, 1.0f});
+			label->set_background_color(0.1f, 0.2f, 0.5f, 0.8f);
+			label = window->create_label(0.5f, 0.5f, "Hello World!", {1.0f, 1.0f, 1.0f, 0.5f});
+			label->set_background_color(0.5f, 0.5f, 0.1f);
+			label = window->create_label(0.75f, 0.75f, "Hello World!", {1.0f, 1.0f, 1.0f, 0.1f});
+			app.run();
 		}
-		cout << "\nStarting example 2" << endl;
-		{
-			auto app = uui::create_application(uui::Application::OPENGL);
-			app->create_window(800, 600, "OpenGl!", [](uui::Window& window) {
-				window.create_component({0.25f, 0.25f, 0.5f, 0.5f}, [](uui::Component& component) {
-					component.set_background_color(0.8f, 0.1f, 0.5f);
-				});
-				window.create_component({0.75f, 0.75f, 0.25f, 0.25f}, [](uui::Component& component) {
-					component.set_background_color(0.2f, 0.1f, 0.5f);
-				});
-			});
+		// cout << "\nStarting example 2" << endl;
+		// {
+		// 	uui::GlApplication app;
+		// 	auto window_1 = app.create_window(800, 600, "OpenGl!");
+		// 	auto comp = window_1->create_component(0.25f, 0.25f, 0.5f, 0.5f);
+		// 	comp->set_background_color(0.8f, 0.1f, 0.5f);
+		// 	comp = window_1->create_component(0.75f, 0.75f, 0.25f, 0.25f);
+		// 	comp->set_background_color(0.2f, 0.1f, 0.5f);
 
-			app->create_window(600, 600, "OpenGL 2!", [](uui::Window& window) {
-				window.create_component({0, 0.5f, 100, 0.5f}, [](uui::Component& component) {
-					component.set_background_color(0.2f, 0.5f, 0.3f);
-				});
-				window.create_label({50, 50, "Hello World!", {0.5f, 1.0f, 0.5f, 1.0f}}, [](uui::Label& label) {
-					label.set_background_color(0.1f, 0.2f, 0.5f);
-				});
-			});
-			app->run();
-		}
+		// 	auto window_2 = app.create_window(600, 600, "OpenGL 2!");
+		// 	comp = window_2->create_component(0, 0.5f, 100, 0.5f);
+		// 	comp->set_background_color(0.2f, 0.5f, 0.3f);
+		// 	auto label = window_2->create_label(50, 50, "Hello World!", {0.5f, 1.0f, 0.5f, 1.0f});
+		// 	label->set_background_color(0.1f, 0.2f, 0.5f);
+		// 	app.run();
+		// }
 	}
 	catch(const std::exception& error)
 	{
diff --git a/src/test/sample.cpp b/src/test/sample.cpp
deleted file mode 100644
index b0d1202..0000000
--- a/src/test/sample.cpp
+++ /dev/null
@@ -1,15 +0,0 @@
-#include "uui/uui.hpp"
-
-int main()
-{
-	auto app = uui::create_application(uui::Application::OPENGL);
-	app->create_window(800, 600, "UUI sample", [](uui::Window& window) {
-		window.create_component({.x = 0, .y = 0, .width = 200, .height = 100}, [](uui::Component& component) {
-			component.set_background_color(1.0f, 0.f, 0.f, 0.5f);
-		});
-		window.create_label(
-			{.x = 0.5f, .y = 0.5f, .text = "Hello world!", .text_color = {0.8f, 0.8f, 0.8f, 1.0f}}, nullptr);
-	});
-	app->run();
-	return 0;
-}
diff --git a/src/uui/application.cpp b/src/uui/application.cpp
index 368eb79..84209ca 100644
--- a/src/uui/application.cpp
+++ b/src/uui/application.cpp
@@ -1,20 +1,3 @@
 #include "uui/application.hpp"
 
-#include <stdexcept>
-
-#include "uui/opengl/application.hpp"
-
-std::shared_ptr<uui::Application> uui::Application::current_application;
-
-std::shared_ptr<uui::Application> uui::create_application(uui::Application::Implementaion implementation)
-{
-	switch(implementation)
-	{
-		case uui::Application::Implementaion::OPENGL:
-			if(uui::Application::current_application != nullptr)
-				throw std::runtime_error("Application error: the application already created");
-			std::shared_ptr<uui::Application> new_application(new uui::GlApplication());
-			uui::Application::current_application = new_application;
-			return new_application;
-	}
-}
+bool uui::Application::application_created = false;
diff --git a/src/uui/opengl/application.cpp b/src/uui/opengl/application.cpp
index 81ceb36..79ed9c6 100644
--- a/src/uui/opengl/application.cpp
+++ b/src/uui/opengl/application.cpp
@@ -3,35 +3,17 @@
 #include <chrono>
 #include <iostream>
 
-#include "uui/opengl/window.hpp"
+uui::GlApplication* uui::GlApplication::application_pointer = nullptr;
 
 uui::GlApplication::GlApplication()
 {
+	if(application_pointer != nullptr)
+		throw std::runtime_error("GlApplication error: the application already created");
 	if constexpr(debug_mode)
 		std::cout << "Creating the GlApplication in debug mode" << std::endl;
 	else
 		std::cout << "Creating the GlApplication in release mode" << std::endl;
-	initialized = false;
-
-	init();
-}
-
-uui::GlApplication::~GlApplication()
-{
-	if constexpr(debug_mode)
-		std::cout << "Destroying the GlApplication" << std::endl;
-	if(initialized)
-		deinit();
-}
-
-void uui::GlApplication::init()
-{
-	if constexpr(debug_mode)
-		std::cout << "Initialize the GlApplication" << std::endl;
-
 	// Init GLFW
-	// Avoiding libdecor would be better
-	// glfwInitHint(GLFW_WAYLAND_LIBDECOR, GLFW_WAYLAND_DISABLE_LIBDECOR);
 	glfwInit();
 	// Set all the required options for GLFW
 	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
@@ -41,24 +23,22 @@ void uui::GlApplication::init()
 	if constexpr(uui::GlApplication::debug_mode)
 		glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, true);
 
-	initialized = true;
+	application_pointer = this;
 }
 
-void uui::GlApplication::deinit()
+uui::GlApplication::~GlApplication()
 {
 	if constexpr(debug_mode)
-		std::cout << "Deinit the GlApplication" << std::endl;
+		std::cout << "Destroying the GlApplication" << std::endl;
 	windows.clear();
 	glfwTerminate();
-	initialized = false;
+	application_pointer = nullptr;
 }
 
 void uui::GlApplication::run()
 {
 	if constexpr(debug_mode)
 		std::cout << "Starting the GlApplication" << std::endl;
-	if(!initialized)
-		init();
 
 	auto start_time = std::chrono::high_resolution_clock::now();
 	auto end_time = start_time;
@@ -71,7 +51,7 @@ void uui::GlApplication::run()
 		if constexpr(debug_mode)
 		{
 			end_time = std::chrono::high_resolution_clock::now();
-			render_duration = std::chrono::duration<float, std::milli>(end_time - start_time).count();
+			render_duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time).count();
 			// std::cout << "Frame " << frame_count << ", duration: " << render_duration << std::endl;
 			if(frame_count > 0.0f && render_duration > 500.0f)
 			{
@@ -95,8 +75,6 @@ void uui::GlApplication::run()
 					glfwMakeContextCurrent((*(windows.end() - 2))->glfw_window);
 					glfwSwapInterval(1);
 				}
-				if constexpr(debug_mode)
-					std::cout << "\nGlApplication closing GlWindow : " << window->title() << std::endl;
 				window->deinit();
 				windows.erase(it);
 				it -= 1;
@@ -107,7 +85,7 @@ void uui::GlApplication::run()
 					window->render();
 				else
 				{
-					if(window->_render_needed && !window->_iconified)
+					if(window->render_needed && !window->iconified)
 						window->render();
 				}
 			}
@@ -117,12 +95,11 @@ void uui::GlApplication::run()
 	}
 	if constexpr(debug_mode)
 		std::cout << "Ending the GlApplication" << std::endl;
-	current_application = nullptr;
 }
 
-void uui::GlApplication::create_window(int width, int height, const std::string& title, uui::InitFunction<Window> init)
+std::shared_ptr<uui::GlWindow> uui::GlApplication::create_window(int width, int height, const std::string& title)
 {
-	auto window = std::shared_ptr<uui::GlWindow>(new uui::GlWindow(current_application, width, height, title));
+	std::shared_ptr<uui::GlWindow> window(new uui::GlWindow(this, windows.size(), width, height, title));
 	window->init();
 	windows.push_back(window);
 	glfwSwapInterval(1);
@@ -131,12 +108,10 @@ void uui::GlApplication::create_window(int width, int height, const std::string&
 		glfwMakeContextCurrent((*(windows.end() - 2))->glfw_window);
 		glfwSwapInterval(0);
 	}
-
-	if(window != nullptr && init != nullptr)
-		init(*window);
+	return window;
 }
 
-std::shared_ptr<uui::Window> uui::GlApplication::get_window(std::size_t index) const
+std::shared_ptr<uui::GlWindow> uui::GlApplication::get_window(size_t index) const
 {
 	if(index > windows.size())
 		throw std::runtime_error("Application doesn't have window at given index");
diff --git a/src/uui/opengl/component.cpp b/src/uui/opengl/component.cpp
index 35c1e10..1a43e76 100644
--- a/src/uui/opengl/component.cpp
+++ b/src/uui/opengl/component.cpp
@@ -3,62 +3,46 @@
 #include <iostream>
 
 #include "uui/opengl/application.hpp"
-#include "uui/opengl/container.hpp"
 #include "uui/opengl/gl_utils.hpp"
 
 uui::GlComponent::GlComponent(
-	std::shared_ptr<uui::GlWindow> window, std::size_t window_index, std::shared_ptr<uui::GlContainer> parent,
-	std::size_t parent_index, const ComponentParams& params)
+	 std::shared_ptr<GlWindow> window, const std::variant<int, float> x, const std::variant<int, float> y,
+	 const std::variant<int, float> width, const std::variant<int, float> height):
+	 window(window),
+	 position_x(x), position_y(y), size_width(width), size_height(height), initialized(false)
 {
-	if constexpr(uui::Application::debug_mode)
-		std::cout << "Creating a GlComponent " << parent_index << std::endl;
+	if constexpr(uui::GlApplication::debug_mode)
+		std::cout << "Creating a GlBox" << std::endl;
 
-	_type = ComponentType::COMPONENT;
-
-	gl_window = window;
-	this->_window = std::static_pointer_cast<uui::Window>(window);
-	this->_window_index = window_index;
-	this->_parent = std::static_pointer_cast<uui::Container>(parent);
-	this->_parent_index = parent_index;
-
-	_initialized = false;
-
-	_position_x = params.x;
-	_position_y = params.y;
-	_width = params.width;
-	_height = params.height;
-
-	_coord_all_relative = true;
-	auto parse_coords = [&](position_t& value) {
+	coord_all_relative = true;
+	auto parse_coords = [&](std::variant<int, float>& value) {
 		if(value.index() == 0)
 		{
 			if(std::get<0>(value) == 0)
 				value = 0.0f;
 			else
-				_coord_all_relative = false;
+				coord_all_relative = false;
 		}
 	};
-	parse_coords(_position_x);
-	parse_coords(_position_y);
-	parse_coords(_width);
-	parse_coords(_height);
+	parse_coords(position_x);
+	parse_coords(position_y);
+	parse_coords(size_width);
+	parse_coords(size_height);
 
-	_background_color = {0.0f, 0.0f, 0.0f, 0.0f};
+	background_color = {0.0f, 0.0f, 0.0f, 0.0f};
 }
 
 uui::GlComponent::~GlComponent()
 {
 	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Destructor GlComponent " << _parent_index << std::endl;
-	if(_initialized)
+		std::cout << "Closing a GlBox" << std::endl;
+	if(initialized)
 		deinit();
-	// if(parent != window)
-	// 	parent->remove_child(0); // TODO
 }
 
 void uui::GlComponent::set_background_color(float r, float g, float b, float a /*=0.0f*/)
 {
-	_background_color = {r, g, b, a};
+	background_color = {r, g, b, a};
 	glBindVertexArray(gl_vao);
 	set_vbo_data();
 	glBindVertexArray(0); // Optional : for safety
@@ -66,8 +50,8 @@ void uui::GlComponent::set_background_color(float r, float g, float b, float a /
 
 void uui::GlComponent::init()
 {
-	if(_initialized)
-		throw std::runtime_error("GlComponent error : calling init while already initialized");
+	if(initialized)
+		throw std::runtime_error("GlBox error : calling init while already initialized");
 
 	glGenVertexArrays(1, &gl_vao);
 	glGenBuffers(1, &gl_vbo);
@@ -80,8 +64,8 @@ void uui::GlComponent::init()
 	set_vbo_data();
 
 	unsigned int indices[] = {
-		0, 1, 3, // first triangle
-		1, 2, 3 // second triangle
+		 0, 1, 3, // first triangle
+		 1, 2, 3 // second triangle
 	};
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, gl_ebo);
 	if constexpr(uui::GlApplication::debug_mode)
@@ -94,73 +78,65 @@ void uui::GlComponent::init()
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 	glBindVertexArray(0);
 
-	_initialized = true;
+	initialized = true;
 }
 
 void uui::GlComponent::set_vbo_data()
 {
-	float vert_x = _position_x.index() == 1
-		? std::get<1>(_position_x)
-		: static_cast<float>(std::get<0>(_position_x)) / static_cast<float>(_window->width());
-	float vert_y = _position_y.index() == 1
-		? std::get<1>(_position_y)
-		: static_cast<float>(std::get<0>(_position_y)) / static_cast<float>(_window->height());
-	float vert_w = _width.index() == 1 ? std::get<1>(_width)
-									   : static_cast<float>(std::get<0>(_width)) / static_cast<float>(_window->width());
-	float vert_h = _height.index() == 1
-		? std::get<1>(_height)
-		: static_cast<float>(std::get<0>(_height)) / static_cast<float>(_window->height());
+	float vert_x =
+		 position_x.index() == 1 ? std::get<1>(position_x) : static_cast<float>(std::get<0>(position_x)) / static_cast<float>(window->width);
+	float vert_y =
+		 position_y.index() == 1 ? std::get<1>(position_y) : static_cast<float>(std::get<0>(position_y)) / static_cast<float>(window->height);
+	float vert_w =
+		 size_width.index() == 1 ? std::get<1>(size_width) : static_cast<float>(std::get<0>(size_width)) / static_cast<float>(window->width);
+	float vert_h = size_height.index() == 1 ? std::get<1>(size_height)
+														 : static_cast<float>(std::get<0>(size_height)) / static_cast<float>(window->height);
 	float x_min = (2.0f * vert_x) - 1.0f;
 	float x_max = x_min + (2.0f * vert_w);
 	float y_min = (-2.0f * vert_y) + 1.0f;
 	float y_max = y_min - (2.0f * vert_h);
+	std::cout << "Sending vbo data with color: " << background_color[0] << ", " << background_color[1] << ", " << background_color[2] << ", "
+				 << background_color[3] << std::endl;
 	// clang-format off
-	float vertices[] =
-	{
-		x_max, y_min, _background_color[0], _background_color[1], _background_color[2], _background_color[3],  // top right
-		x_max, y_max, _background_color[0], _background_color[1], _background_color[2], _background_color[3],  // bottom right
-		x_min, y_max, _background_color[0], _background_color[1], _background_color[2], _background_color[3],  // bottom left
-		x_min, y_min, _background_color[0], _background_color[1], _background_color[2], _background_color[3]   // top left
+	float vertices[] = {
+		x_max, y_min, background_color[0] , background_color[1], background_color[2], background_color[3], // top right
+		x_max, y_max, background_color[0] , background_color[1], background_color[2], background_color[3], // bottom right
+		x_min, y_max, background_color[0] , background_color[1], background_color[2], background_color[3], // bottom left
+		x_min, y_min, background_color[0] , background_color[1], background_color[2], background_color[3]  // top left
 	};
 	// clang-format on
 	glBindBuffer(GL_ARRAY_BUFFER, gl_vbo);
 	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
 
 	glVertexAttribPointer(
-		0, // index
-		2, // size
-		GL_FLOAT, // type
-		GL_FALSE, // enable normalization,
-		6 * sizeof(float), // stride
-		(void*)0 // offset
+		 0, // index
+		 2, // size
+		 GL_FLOAT, // type
+		 GL_FALSE, // enable normalization,
+		 6 * sizeof(float), // stride
+		 (void*)0 // offset
 	);
 	glEnableVertexAttribArray(0);
 	glVertexAttribPointer(
-		1, // index
-		4, // size
-		GL_FLOAT, // type
-		GL_FALSE, // enable normalization,
-		6 * sizeof(float), // stride
-		(void*)(2 * sizeof(float)) // offset
+		 1, // index
+		 4, // size
+		 GL_FLOAT, // type
+		 GL_FALSE, // enable normalization,
+		 6 * sizeof(float), // stride
+		 (void*)(2 * sizeof(float)) // offset
 	);
 	glEnableVertexAttribArray(1);
 }
 
 void uui::GlComponent::deinit()
 {
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Deinit GlComponent " << _parent_index << std::endl;
-
-	if(!_initialized)
-		throw std::runtime_error("GlComponent error : calling deinit while not initialized");
+	if(!initialized)
+		throw std::runtime_error("GlBox error : calling deinit while not initialized");
 
 	glDeleteVertexArrays(1, &gl_vao);
 	glDeleteBuffers(1, &gl_vbo);
 	glDeleteBuffers(1, &gl_ebo);
-
-	_window = nullptr;
-	_parent = nullptr;
-	_initialized = false;
+	initialized = false;
 }
 
 void uui::GlComponent::render()
@@ -171,12 +147,8 @@ void uui::GlComponent::render()
 
 void uui::GlComponent::on_resize()
 {
-	bool is_in_stack =
-		_parent != nullptr && (_parent->type() == ComponentType::FLEX || _parent->type() == ComponentType::STACK);
-	if(!_coord_all_relative || is_in_stack)
+	if(!coord_all_relative)
 	{
-		if(is_in_stack)
-			std::tie(_position_x, _position_y) = _parent->get_child_position(_parent_index);
 		glBindVertexArray(gl_vao);
 		set_vbo_data();
 		glBindVertexArray(0); // Optional : for safety
diff --git a/src/uui/opengl/container_interface.cpp b/src/uui/opengl/container_interface.cpp
deleted file mode 100644
index 2abe608..0000000
--- a/src/uui/opengl/container_interface.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-#include "uui/opengl/container_interface.hpp"
-
-#include <iostream>
-
-#include "uui/opengl/component.hpp"
-
-std::size_t uui::GlContainerInterface::push_child(std::shared_ptr<uui::Component> child [[maybe_unused]])
-{
-	throw std::runtime_error("GlContainerInterface error : should only push GlComponent child, not Component");
-}
-
-std::size_t uui::GlContainerInterface::push_child(std::shared_ptr<uui::GlComponent> child)
-{
-	components.push_back(child);
-	return components.size() - 1;
-}
-
-std::shared_ptr<uui::Component> uui::GlContainerInterface::get_child(std::size_t index) const
-{
-	return components.at(index);
-}
-
-void uui::GlContainerInterface::remove_child(std::size_t index)
-{
-	components.at(index) = nullptr;
-};
-
-std::tuple<int, int> uui::GlContainerInterface::get_child_position(const std::size_t child_index [[maybe_unused]]) const
-{
-	return {0, 0};
-}
-
-uui::GlContainerInterface::~GlContainerInterface()
-{
-	if constexpr(uui::Application::debug_mode)
-		std::cout << "Destroying GlContainerInterface" << std::endl;
-	components.clear();
-}
diff --git a/src/uui/opengl/flex.cpp b/src/uui/opengl/flex.cpp
deleted file mode 100644
index e38b6e0..0000000
--- a/src/uui/opengl/flex.cpp
+++ /dev/null
@@ -1,124 +0,0 @@
-#include "uui/opengl/flex.hpp"
-
-#include <iostream>
-
-#include "uui/opengl/gl_utils.hpp"
-
-uui::GlFlex::GlFlex(
-	std::shared_ptr<uui::GlWindow> window, std::size_t window_index, std::shared_ptr<uui::GlContainer> parent,
-	std::size_t parent_index, const StackParams& params):
-	GlComponent(window, window_index, parent, parent_index, {params.x, params.y, 0.0f, 0.0f}),
-	GlStack(window, window_index, parent, parent_index, params)
-{
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating a GlFlex " << parent_index << std::endl;
-
-	_type = ComponentType::FLEX;
-
-	_coord_all_relative = false;
-}
-
-std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_index) const
-{
-	const int initial_x = _position_x.index() == 0
-		? std::get<0>(_position_x)
-		: static_cast<int>(std::get<1>(_position_x) * static_cast<float>(_window->width()));
-	const int initial_y = _position_y.index() == 0
-		? std::get<0>(_position_y)
-		: static_cast<int>(std::get<1>(_position_y) * static_cast<float>(_window->height()));
-
-	if(child_index == 0)
-		return {initial_x, initial_y};
-	if(child_index >= components.size())
-		throw std::runtime_error("GlStack error: child_index greater than children count");
-
-	auto get_child_size = [&](std::size_t index) -> std::tuple<int, int> {
-		int width = 0;
-		int height = 0;
-		if(components[index] != nullptr)
-		{
-			auto& component = components[index];
-			if(component->width().index() == 1)
-				width = static_cast<int>(std::get<1>(component->width()) * static_cast<float>(_window->width()));
-			else
-				width = std::get<0>(component->width());
-			if(component->height().index() == 1)
-				height = static_cast<int>(std::get<1>(component->height()) * static_cast<float>(_window->height()));
-			else
-				height = std::get<0>(component->height());
-		}
-		return {width, height};
-	};
-	int x = initial_x;
-	int y = initial_y;
-	if(direction == Direction::HORIZONTAL)
-	{
-		int child_width;
-		int child_height;
-		int max_height = 0;
-
-		std::tie(child_width, child_height) = get_child_size(0);
-		if(child_height > max_height)
-			max_height = child_height;
-		x += child_width;
-		for(std::size_t index = 1; index < child_index; index += 1)
-		{
-			std::tie(child_width, child_height) = get_child_size(index);
-			if(child_height > max_height)
-				max_height = child_height;
-			if(x != initial_x && x + child_width > _window->width())
-			{
-				x = initial_x + child_width;
-				y += max_height;
-				max_height = child_height;
-			}
-			else
-				x += child_width;
-		}
-		if(components[child_index] != nullptr)
-		{
-			std::tie(child_width, child_height) = get_child_size(child_index);
-			if(x != initial_x && x + child_width > _window->width())
-			{
-				x = initial_x;
-				y += max_height;
-			}
-		}
-	}
-	else
-	{
-		int child_width;
-		int child_height;
-		int max_width = 0;
-
-		std::tie(child_width, child_height) = get_child_size(0);
-		if(child_width > max_width)
-			max_width = child_width;
-		y += child_height;
-		for(std::size_t index = 1; index < child_index; index += 1)
-		{
-			std::tie(child_width, child_height) = get_child_size(index);
-			if(child_width > max_width)
-				max_width = child_width;
-			if(y != initial_y && y + child_height > _window->height())
-			{
-				y = initial_y + child_height;
-				x += max_width;
-				max_width = child_width;
-			}
-			else
-				y += child_height;
-		}
-		if(components[child_index] != nullptr)
-		{
-			std::tie(child_width, child_height) = get_child_size(child_index);
-			if(y != initial_y && y + child_height > _window->height())
-			{
-				y = initial_y;
-				x += max_width;
-			}
-		}
-	}
-
-	return {x, y};
-}
diff --git a/src/uui/opengl/font_manager.cpp b/src/uui/opengl/font_manager.cpp
index 18e67f8..546ae6e 100644
--- a/src/uui/opengl/font_manager.cpp
+++ b/src/uui/opengl/font_manager.cpp
@@ -6,15 +6,12 @@
 #include <algorithm>
 #include <iostream>
 
+#include "uui/config.hpp"
 #include "uui/opengl/application.hpp"
 #include "uui/opengl/gl_utils.hpp"
 #include "uui/shader.hpp"
-#include "uui/types.hpp"
 
-uui::GlFontManager::GlFontManager()
-{
-	initialized = false;
-}
+uui::GlFontManager::GlFontManager(): initialized(false) {}
 
 uui::GlFontManager::~GlFontManager()
 {
@@ -28,7 +25,7 @@ void uui::GlFontManager::init()
 		throw std::runtime_error("GlFontManager error : calling init while initialized");
 
 	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Init GlFontManager" << std::endl;
+		std::cout << "Init glFontManager" << std::endl;
 
 	if(FT_Init_FreeType(&ft))
 		throw std::runtime_error("ERROR::FREETYPE: Could not init FreeType Library");
@@ -120,9 +117,6 @@ void uui::GlFontManager::deinit()
 	if(!initialized)
 		throw std::runtime_error("GlFontManager error : calling deinit while not initialized");
 
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Deinit GlFontManager" << std::endl;
-
 	for(const auto& font: fonts) glDeleteTextures(1, &font.atlas_texture);
 	glDeleteBuffers(1, &gl_vbo);
 	glDeleteBuffers(1, &gl_vao);
@@ -131,7 +125,7 @@ void uui::GlFontManager::deinit()
 	initialized = false;
 }
 
-const uui::GlFontManager::Font& uui::GlFontManager::init_font(const std::string& font_path, unsigned int font_size)
+const uui::GlFontManager::Font& uui::GlFontManager::init_font(const std::string& font_path, size_t font_size)
 {
 	fonts.emplace_back();
 	auto& font = fonts.back();
@@ -173,7 +167,7 @@ const uui::GlFontManager::Font& uui::GlFontManager::init_font(const std::string&
 	glLinkProgram(gl_program);
 
 	// Create a texture that will be used to hold all ASCII glyphs
-	glActiveTexture(GlConfig::FONT_TEXTURE_UNIT);
+	glActiveTexture(Config::FONT_TEXTURE_UNIT);
 	glGenTextures(1, &font.atlas_texture);
 	glBindTexture(GL_TEXTURE_2D, font.atlas_texture);
 
@@ -212,8 +206,7 @@ const uui::GlFontManager::Font& uui::GlFontManager::init_font(const std::string&
 		}
 
 		glTexSubImage2D(
-			GL_TEXTURE_2D, 0, offset_x, offset_y, glyph->bitmap.width, glyph->bitmap.rows, GL_RED, GL_UNSIGNED_BYTE,
-			glyph->bitmap.buffer);
+			 GL_TEXTURE_2D, 0, offset_x, offset_y, glyph->bitmap.width, glyph->bitmap.rows, GL_RED, GL_UNSIGNED_BYTE, glyph->bitmap.buffer);
 		font.char_infos[i].advance_x = glyph->advance.x >> 6;
 		font.char_infos[i].advance_y = glyph->advance.y >> 6;
 
@@ -235,13 +228,13 @@ const uui::GlFontManager::Font& uui::GlFontManager::init_font(const std::string&
 }
 
 std::tuple<int, int> uui::GlFontManager::get_text_size(
-	const std::string& text, uui::GlFontManager::Font& font, float scale_x, float scale_y)
+	 const std::string& text, uui::GlFontManager::Font& font, float scale_x, float scale_y)
 {
 	float width = 0.0f;
 	float height = 0.0f;
 	for(auto current_char: text)
 	{
-		const auto& char_info = font.char_infos[static_cast<std::size_t>(current_char)];
+		const auto& char_info = font.char_infos[static_cast<size_t>(current_char)];
 		width += char_info.advance_x * scale_x;
 		// height = std::max(height, char_info.bitmap_top + char_info.bitmap_height * scale_y);
 		height = std::max(height, roundf(char_info.bitmap_height * scale_y));
@@ -250,14 +243,14 @@ std::tuple<int, int> uui::GlFontManager::get_text_size(
 }
 
 void uui::GlFontManager::render_text(
-	const std::string& text, uui::GlFontManager::Font& font, float x, float y, float scale_x, float scale_y,
-	const std::tuple<float, float, float, float>& text_color)
+	 const std::string& text, uui::GlFontManager::Font& font, float x, float y, float scale_x, float scale_y,
+	 const std::tuple<float, float, float, float>& text_color)
 {
 	GLuint gl_prev_program;
 	glGetIntegerv(GL_CURRENT_PROGRAM, (GLint*)(&gl_prev_program));
 	glUseProgram(gl_program);
 
-	glActiveTexture(GlConfig::FONT_TEXTURE_UNIT);
+	glActiveTexture(Config::FONT_TEXTURE_UNIT);
 	auto [color_r, color_g, color_b, color_a] = text_color;
 	glUniform4f(glGetUniformLocation(gl_program, "textColor"), color_r, color_g, color_b, color_a);
 	glBindVertexArray(gl_vao);
@@ -275,7 +268,7 @@ void uui::GlFontManager::render_text(
 	float out_base_y = y;
 	for(auto current_char: text)
 	{
-		const auto& char_info = font.char_infos[static_cast<std::size_t>(current_char)];
+		const auto& char_info = font.char_infos[static_cast<size_t>(current_char)];
 		//  Calculate the vertex and texture coordinates
 		float char_x = out_base_x + char_info.bitmap_left * scale_x;
 		float char_y = out_base_y - char_info.bitmap_top * scale_y;
@@ -291,16 +284,15 @@ void uui::GlFontManager::render_text(
 			continue;
 
 		// clang-format off
-		float current_vertex[24] =
-		{
-			char_x, char_y, char_info.texture_x, char_info.texture_y, // top_left
-			char_x + w, char_y, char_info.texture_x + char_info.bitmap_width / font.atlas_width, char_info.texture_y, // top-right
-			char_x, char_y + h, char_info.texture_x, char_info.texture_y + char_info.bitmap_height / font.atlas_height, // bottom-right
-			char_x + w, char_y, char_info.texture_x + char_info.bitmap_width / font.atlas_width, char_info.texture_y, // top-right
-			char_x, char_y + h, char_info.texture_x, char_info.texture_y + char_info.bitmap_height / font.atlas_height, // bottom-left
-			char_x + w, char_y + h, char_info.texture_x + char_info.bitmap_width / font.atlas_width,
-			char_info.texture_y + char_info.bitmap_height / font.atlas_height // bottom-right
-		};
+		float current_vertex[24] = {
+			 char_x, char_y, char_info.texture_x, char_info.texture_y, // top_left
+			 char_x + w, char_y, char_info.texture_x + char_info.bitmap_width / font.atlas_width, char_info.texture_y, // top-right
+			 char_x, char_y + h, char_info.texture_x, char_info.texture_y + char_info.bitmap_height / font.atlas_height, // bottom-right
+			 char_x + w, char_y, char_info.texture_x + char_info.bitmap_width / font.atlas_width, char_info.texture_y, // top-right
+			 char_x, char_y + h, char_info.texture_x, char_info.texture_y + char_info.bitmap_height / font.atlas_height, // bottom-left
+			 char_x + w, char_y + h, char_info.texture_x + char_info.bitmap_width / font.atlas_width,
+			  char_info.texture_y + char_info.bitmap_height / font.atlas_height // bottom-right
+			};
 		std::memcpy(vertices.data() + (char_count * 24), current_vertex, 24 * sizeof(float));
 		// clang-format on
 		char_count += 1;
diff --git a/src/uui/opengl/label.cpp b/src/uui/opengl/label.cpp
index fd16e89..5ba7478 100644
--- a/src/uui/opengl/label.cpp
+++ b/src/uui/opengl/label.cpp
@@ -2,39 +2,34 @@
 
 #include <iostream>
 
-#include "uui/opengl/font_manager.hpp"
 #include "uui/opengl/gl_utils.hpp"
 
 uui::GlLabel::GlLabel(
-	std::shared_ptr<uui::GlWindow> window, std::size_t window_index, std::shared_ptr<uui::GlContainer> parent,
-	std::size_t parent_index, const LabelParams& params):
-	GlComponent(window, window_index, parent, parent_index, {params.x, params.y, 0.0f, 0.0f}), text(params.text),
-	text_color(params.text_color)
+	 std::shared_ptr<uui::GlWindow> window, const std::variant<int, float> x, const std::variant<int, float> y, const std::string& text,
+	 const std::tuple<float, float, float, float>& text_color):
+	 GlComponent(window, x, y, 0.0f, 0.0f),
+	 text(text), text_color(text_color)
 {
-	if constexpr(uui::Application::debug_mode)
-		std::cout << "Creating GlLabel " << parent_index << std::endl;
-
-	_type = ComponentType::LABEL;
+	if constexpr(uui::GlApplication::debug_mode)
+		std::cout << "Creating a GlLabel" << std::endl;
 
 	font_index = 0;
-	std::tie(text_width, text_height) =
-		window->font_manager->get_text_size(text, window->font_manager->fonts[font_index], 1.0f, 1.0f);
-	_width = text_width;
-	_height = text_height;
-	_coord_all_relative = false;
+	std::tie(text_width, text_height) = window->font_manager.get_text_size(text, window->font_manager.fonts[font_index], 1.0f, 1.0f);
+	size_width = text_width;
+	size_height = text_height;
+	coord_all_relative = false;
 }
 
 void uui::GlLabel::render()
 {
-	float text_x = _position_x.index() == 1 ? std::get<1>(_position_x) * static_cast<float>(_window->width())
-											: static_cast<float>(std::get<0>(_position_x));
-	float text_y = _position_y.index() == 1 ? std::get<1>(_position_y) * static_cast<float>(_window->height())
-											: static_cast<float>(std::get<0>(_position_y));
+	float text_x =
+		 position_x.index() == 1 ? std::get<1>(position_x) * static_cast<float>(window->width) : static_cast<float>(std::get<0>(position_x));
+	float text_y =
+		 position_y.index() == 1 ? std::get<1>(position_y) * static_cast<float>(window->height) : static_cast<float>(std::get<0>(position_y));
 	text_y += static_cast<float>(text_height) - 1;
 
 	glBindVertexArray(gl_vao);
 	glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, (void*)0);
-	_window->font_manager->render_text(
-		text.c_str(), _window->font_manager->fonts.front(), text_x, text_y, 1.0f, 1.0f, text_color);
+	window->font_manager.render_text(text.c_str(), window->font_manager.fonts.front(), text_x, text_y, 1.0f, 1.0f, text_color);
 	glBindVertexArray(0);
 }
diff --git a/src/uui/opengl/stack.cpp b/src/uui/opengl/stack.cpp
deleted file mode 100644
index 5fa8862..0000000
--- a/src/uui/opengl/stack.cpp
+++ /dev/null
@@ -1,101 +0,0 @@
-#include "uui/opengl/stack.hpp"
-
-#include <iostream>
-
-#include "uui/opengl/gl_utils.hpp"
-#include "uui/opengl/label.hpp"
-
-uui::GlStack::GlStack(
-	std::shared_ptr<uui::GlWindow> window, std::size_t window_index, std::shared_ptr<uui::GlContainer> parent,
-	std::size_t parent_index, const StackParams& params):
-	GlComponent(window, window_index, parent, parent_index, {params.x, params.y, 0.0f, 0.0f})
-{
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating GlStack " << parent_index << std::endl;
-
-	_type = ComponentType::STACK;
-
-	direction = params.direction;
-
-	_coord_all_relative = false;
-}
-
-void uui::GlStack::create_component(const StackComponentParams& params, uui::InitFunction<uui::Component> init)
-{
-	if(!_initialized)
-		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
-
-	glfwMakeContextCurrent(gl_window->glfw_window);
-	std::shared_ptr<uui::GlComponent> component(new uui::GlComponent(
-		gl_window, gl_window->components.size(), std::dynamic_pointer_cast<uui::GlContainer>(shared_from_this()),
-		components.size(), {0, 0, params.width, params.height}));
-	push_child(component);
-	component->init();
-	std::tie(component->_position_x, component->_position_y) = get_child_position(components.size() - 1);
-	gl_window->components.push_back(component);
-
-	if(component != nullptr)
-		init(*component);
-}
-
-void uui::GlStack::create_label(const StackLabelParams& params, uui::InitFunction<uui::Label> init)
-{
-	if(!_initialized)
-		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
-
-	glfwMakeContextCurrent(gl_window->glfw_window);
-	std::shared_ptr<uui::GlLabel> label(new uui::GlLabel(
-		gl_window, gl_window->components.size(), std::dynamic_pointer_cast<uui::GlContainer>(shared_from_this()),
-		components.size(), {0, 0, params.text, params.text_color}));
-	push_child(std::static_pointer_cast<uui::GlComponent>(label));
-	label->init();
-	std::tie(label->_position_x, label->_position_y) = get_child_position(components.size() - 1);
-	gl_window->components.push_back(label);
-
-	if(label != nullptr && init != nullptr)
-		init(*label);
-}
-
-std::tuple<int, int> uui::GlStack::get_child_position(const std::size_t child_index) const
-{
-	int x = _position_x.index() == 0
-		? std::get<0>(_position_x)
-		: static_cast<int>(std::get<1>(_position_x) * static_cast<float>(_window->width()));
-	int y = _position_y.index() == 0
-		? std::get<0>(_position_y)
-		: static_cast<int>(std::get<1>(_position_y) * static_cast<float>(_window->height()));
-
-	if(child_index == 0)
-		return {x, y};
-	if(child_index >= components.size())
-		throw std::runtime_error("GlStack error: child_index greater than children count");
-
-	if(direction == Direction::HORIZONTAL)
-	{
-		for(std::size_t index = 0; index < child_index; index += 1)
-			if(components[index] != nullptr)
-			{
-				auto& component = components[index];
-				if(component->width().index() == 1)
-					x += static_cast<int>(std::get<1>(component->width()) * static_cast<float>(_window->width()));
-				else
-					x += std::get<0>(component->width());
-			}
-	}
-	else
-	{
-		for(std::size_t index = 0; index < child_index; index += 1)
-		{
-			if(components[index] != nullptr)
-			{
-				auto& component = components[index];
-				if(component->height().index() == 1)
-					y += static_cast<int>(std::get<1>(component->height()) * static_cast<float>(_window->height()));
-				else
-					y += std::get<0>(component->height());
-			}
-		}
-	}
-
-	return {x, y};
-}
diff --git a/src/uui/opengl/window.cpp b/src/uui/opengl/window.cpp
index a139ba7..d728d77 100644
--- a/src/uui/opengl/window.cpp
+++ b/src/uui/opengl/window.cpp
@@ -3,15 +3,12 @@
 #include <iostream>
 
 #include "uui/opengl/component.hpp"
-#include "uui/opengl/flex.hpp"
 #include "uui/opengl/gl_utils.hpp"
 #include "uui/opengl/label.hpp"
-#include "uui/opengl/stack.hpp"
 #include "uui/shader.hpp"
 
-static void APIENTRY glDebugOutput(
-	GLenum source, GLenum type, unsigned int id, GLenum severity, GLsizei length [[maybe_unused]], const char* message,
-	const void* userParam [[maybe_unused]])
+static void APIENTRY
+glDebugOutput(GLenum source, GLenum type, unsigned int id, GLenum severity, GLsizei length, const char* message, const void* userParam)
 {
 	// ignore non-significant error/warning codes
 	if(id == 131169 || id == 131185 || id == 131218 || id == 131204)
@@ -60,77 +57,55 @@ void uui::GlWindow::glfw_resize_callback(GLFWwindow* window, int width, int heig
 	glfwMakeContextCurrent(window);
 	auto gl_window = reinterpret_cast<uui::GlWindow*>(glfwGetWindowUserPointer(window));
 	glViewport(0, 0, width, height);
-	gl_window->_width = width;
-	gl_window->_height = height;
-	gl_window->_render_needed = true;
-	gl_window->_resize_needed = true;
+	gl_window->width = width;
+	gl_window->height = height;
+	gl_window->render_needed = true;
+	gl_window->resize_needed = true;
 
 	glm::mat4 projection = glm::ortho(0.0f, static_cast<float>(width), static_cast<float>(height), 0.0f);
 	glfwMakeContextCurrent(window);
-	glUseProgram(gl_window->gl_font_manager->gl_program);
-	glUniformMatrix4fv(
-		glGetUniformLocation(gl_window->gl_font_manager->gl_program, "projection"), 1, GL_FALSE,
-		glm::value_ptr(projection));
+	glUseProgram(gl_window->font_manager.gl_program);
+	glUniformMatrix4fv(glGetUniformLocation(gl_window->font_manager.gl_program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
 }
 
 void uui::GlWindow::glfw_iconify_callback(GLFWwindow* window, int iconified)
 {
 	auto gl_window = reinterpret_cast<uui::GlWindow*>(glfwGetWindowUserPointer(window));
-	gl_window->_iconified = iconified;
+	gl_window->iconified = iconified;
 }
 
-void uui::GlWindow::glfw_key_callback(
-	GLFWwindow* window, int key, int scancode [[maybe_unused]], int action, int mods [[maybe_unused]])
+void uui::GlWindow::glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
 {
 	if(key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
 		glfwSetWindowShouldClose(window, true);
 }
 
-// void uui::GlWindow::glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
-// {
-// 	if (button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS)
-// 	{}
-// }
-
-uui::GlWindow::GlWindow(std::shared_ptr<uui::Application> app, int width, int height, const std::string& title)
+uui::GlWindow::GlWindow(uui::GlApplication* app, size_t index, int width, int height, const std::string& title):
+	 app(app), width(width), height(height), render_needed(true), resize_needed(false), iconified(false), index(index), initialized(false)
 {
-	_type = ComponentType::WINDOW;
-
-	_app = app;
-	_initialized = false;
-
-	_title = title;
-	_width = width;
-	_height = height;
-	_render_needed = true;
-	_resize_needed = false;
-	_iconified = false;
-
-	if constexpr(uui::Application::debug_mode)
-		std::cout << "Creating GlWindow : " << title << std::endl;
+	if constexpr(uui::GlApplication::debug_mode)
+		std::cout << "Creating a GlWindow" << std::endl;
+	this->title = title;
 }
 
 uui::GlWindow::~GlWindow()
 {
-	if constexpr(uui::Application::debug_mode)
-		std::cout << "Destructor GlWindow : " << _title << std::endl;
-	if(_initialized)
+	if constexpr(uui::GlApplication::debug_mode)
+		std::cout << "Closing a GlWindow" << std::endl;
+	if(initialized)
 	{
-		if constexpr(uui::Application::debug_mode)
-			std::cout << "Destructor-deinit GlWindow : " << _title << std::endl;
+		if constexpr(uui::GlApplication::debug_mode)
+			std::cout << "Destructor-deinit a GlWindow" << std::endl;
 		deinit();
 	}
 }
 
 void uui::GlWindow::init()
 {
-	if(_initialized)
+	if(initialized)
 		throw std::runtime_error("GlWindow error : calling init while already initialized");
 
-	gl_font_manager = std::make_shared<uui::GlFontManager>();
-	font_manager = std::static_pointer_cast<uui::FontManager>(gl_font_manager);
-
-	glfw_window = glfwCreateWindow(_width, _height, _title.c_str(), NULL, NULL);
+	glfw_window = glfwCreateWindow(width, height, title.c_str(), NULL, NULL);
 	if(glfw_window == NULL)
 		throw std::runtime_error("GLWindow : failed to create GLFW window");
 	glfwMakeContextCurrent(glfw_window);
@@ -226,35 +201,31 @@ void uui::GlWindow::init()
 	glDeleteShader(vertex_shader);
 	glDeleteShader(fragment_shader);
 
-	gl_font_manager->init();
-	glUseProgram(gl_font_manager->gl_program);
-	glm::mat4 projection = glm::ortho(0.0f, static_cast<float>(_width), static_cast<float>(_height), 0.0f);
-	glUniformMatrix4fv(
-		glGetUniformLocation(gl_font_manager->gl_program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
+	font_manager.init();
+	glUseProgram(font_manager.gl_program);
+	glm::mat4 projection = glm::ortho(0.0f, static_cast<float>(width), static_cast<float>(height), 0.0f);
+	glUniformMatrix4fv(glGetUniformLocation(font_manager.gl_program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
 	glUseProgram(gl_program);
 
-	_initialized = true;
+	initialized = true;
 }
 
 void uui::GlWindow::deinit()
 {
-	if(!_initialized)
+	if(!initialized)
 		throw std::runtime_error("GlWindow error : calling deinit while not initialized");
 
 	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Deinit GlWindow : " << _title << std::endl;
+		std::cout << "Deinit a GlWindow" << std::endl;
 
 	glfwMakeContextCurrent(glfw_window);
 	glDeleteProgram(gl_program);
-	for(auto& gl_component: components) gl_component->deinit();
+	for(auto& component: components) component->deinit();
 	components.clear();
-	gl_font_manager->deinit();
+	font_manager.deinit();
 	glfwDestroyWindow(glfw_window);
 
-	_app = nullptr;
-	font_manager = nullptr;
-	gl_font_manager = nullptr;
-	_initialized = false;
+	initialized = false;
 }
 
 void uui::GlWindow::render()
@@ -264,69 +235,41 @@ void uui::GlWindow::render()
 	glClear(GL_COLOR_BUFFER_BIT);
 
 	glUseProgram(gl_program);
-	if(_resize_needed)
+	if(resize_needed)
 	{
 		for(auto& component: components) component->on_resize();
-		_resize_needed = false;
+		resize_needed = false;
 	}
 	for(auto& component: components) component->render();
 	glfwSwapBuffers(glfw_window);
 
-	_render_needed = false;
+	render_needed = false;
 }
 
-void uui::GlWindow::create_component(const uui::ComponentParams& params, uui::InitFunction<Component> init)
+std::shared_ptr<uui::GlComponent> uui::GlWindow::create_component(
+	 const std::variant<int, float> x, const std::variant<int, float> y, const std::variant<int, float> width,
+	 const std::variant<int, float> height)
 {
-	if(!_initialized)
+	if(!initialized)
 		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
 
 	glfwMakeContextCurrent(glfw_window);
-	std::shared_ptr<uui::GlComponent> component(new uui::GlComponent(shared_from_this(), components.size(), params));
-	push_child(component);
+	std::shared_ptr<uui::GlComponent> component(new uui::GlComponent(app->get_window(index), x, y, width, height));
 	component->init();
-
-	if(component != nullptr && init != nullptr)
-		init(*component);
+	components.push_back(component);
+	return component;
 }
 
-void uui::GlWindow::create_label(const LabelParams& params, uui::InitFunction<Label> init)
+std::shared_ptr<uui::GlLabel> uui::GlWindow::create_label(
+	 const std::variant<int, float> x, const std::variant<int, float> y, const std::string& text,
+	 const std::tuple<float, float, float, float>& text_color)
 {
-	if(!_initialized)
-		throw std::runtime_error("GlWindow error : cannot create label while not initialized");
+	if(!initialized)
+		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
 
 	glfwMakeContextCurrent(glfw_window);
-	std::shared_ptr<uui::GlLabel> label(new uui::GlLabel(shared_from_this(), components.size(), params));
-	push_child(std::static_pointer_cast<uui::GlComponent>(label));
+	std::shared_ptr<uui::GlLabel> label(new uui::GlLabel(app->get_window(index), x, y, text, text_color));
 	label->init();
-
-	if(label != nullptr && init != nullptr)
-		init(*label);
-}
-
-void uui::GlWindow::create_flex(const StackParams& params, uui::InitFunction<Flex> init)
-{
-	if(!_initialized)
-		throw std::runtime_error("GlWindow error : cannot create flex while not initialized");
-
-	glfwMakeContextCurrent(glfw_window);
-	std::shared_ptr<uui::GlFlex> flex(new uui::GlFlex(shared_from_this(), components.size(), params));
-	push_child(std::static_pointer_cast<uui::GlComponent>(flex));
-	flex->init();
-
-	if(flex != nullptr && init != nullptr)
-		init(*flex);
-}
-
-void uui::GlWindow::create_stack(const StackParams& params, uui::InitFunction<Stack> init)
-{
-	if(!_initialized)
-		throw std::runtime_error("GlWindow error : cannot create stack while not initialized");
-
-	glfwMakeContextCurrent(glfw_window);
-	std::shared_ptr<uui::GlStack> stack(new uui::GlStack(shared_from_this(), components.size(), params));
-	push_child(std::static_pointer_cast<uui::GlComponent>(stack));
-	stack->init();
-
-	if(stack != nullptr && init != nullptr)
-		init(*stack);
+	components.push_back(label);
+	return label;
 }
diff --git a/src/uui/shader.cpp b/src/uui/shader.cpp
index ea8e207..2ce9266 100644
--- a/src/uui/shader.cpp
+++ b/src/uui/shader.cpp
@@ -1,7 +1,7 @@
 #include "uui/shader.hpp"
 
 #include <fstream>
-#include <ios>
+
 
 std::vector<char> uui::readFile(const std::string& filename)
 {
@@ -10,10 +10,10 @@ std::vector<char> uui::readFile(const std::string& filename)
 	if(!file.is_open())
 		throw std::runtime_error("failed to open file!");
 
-	std::size_t fileSize = static_cast<std::size_t>(file.tellg());
+	size_t fileSize = (size_t)file.tellg();
 	std::vector<char> buffer(fileSize);
 	file.seekg(0);
-	file.read(buffer.data(), static_cast<std::streamsize>(fileSize));
+	file.read(buffer.data(), fileSize);
 	file.close();
 
 	return buffer;
diff --git a/umake b/umake
index 933dea2..f5965cc 160000
--- a/umake
+++ b/umake
@@ -1 +1 @@
-Subproject commit 933dea2b9e9da0b03489ea9dca3cd597fdd2d09e
+Subproject commit f5965cc91e7eb27d1def78113301e7ec28fad54a