diff --git a/include/uui/application.hpp b/include/uui/application.hpp
index 151ca36..17c7d2f 100644
--- a/include/uui/application.hpp
+++ b/include/uui/application.hpp
@@ -3,17 +3,34 @@
 #include <memory>
 #include <string>
 
-#include "window.hpp"
+#include "uui/config.hpp"
 
 namespace uui
 {
+class Window;
 class Application
 {
 public:
+	enum Implementaion
+	{
+		OPENGL
+	};
+
 	virtual void run() = 0;
-	// virtual std::weak_ptr<Window> add_window(int width, int height, const std::string& title) = 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() {};
 
 protected:
-	static bool application_created;
+	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);
 };
+
+std::shared_ptr<Application> create_application(Application::Implementaion implementation);
 } // namespace uui
diff --git a/include/uui/component.hpp b/include/uui/component.hpp
index 53a4c50..208720a 100644
--- a/include/uui/component.hpp
+++ b/include/uui/component.hpp
@@ -1,30 +1,43 @@
 #pragma once
 
 #include <array>
-#include <variant>
+#include <memory>
 
 #include "uui/config.hpp"
+#include "uui/window.hpp"
 
 namespace uui
 {
+class Container;
 class Component
 {
 public:
-	Component(const position_t x, const position_t y, const position_t width, const position_t 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;
+	virtual void set_background_color(float r, float g, float b, float a = 1.0f) = 0;
 
 protected:
-	position_t position_x;
-	position_t position_y;
-	position_t size_width;
-	position_t size_height;
+	#ifdef DEBUG
+	constexpr static bool debug_mode = true;
+	#else
+	constexpr static bool debug_mode = false;
+	#endif
+
+	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::position_t size_width;
+	uui::position_t size_height;
+
+	bool coord_all_relative;
 
 	std::array<float, 4> background_color;
+
+	bool initialized;
+
+	virtual void render() = 0;
 };
 
 } // namespace uui
diff --git a/include/uui/config.hpp b/include/uui/config.hpp
index a45f341..7e8ab70 100644
--- a/include/uui/config.hpp
+++ b/include/uui/config.hpp
@@ -1,16 +1,11 @@
 #pragma once
 
+#include <functional>
 #include <variant>
 
-#include "graphic_context.hpp"
-
-namespace Config
-{
-constexpr unsigned int FONT_TEXTURE_UNIT = GL_TEXTURE0;
-}
-
 namespace uui
 {
+template<typename T> using InitFunction = const std::function<void(T&)>&;
 typedef std::variant<int, float> position_t;
 typedef std::variant<int, float> size_t;
 enum Direction
diff --git a/include/uui/container.hpp b/include/uui/container.hpp
new file mode 100644
index 0000000..f5a3d84
--- /dev/null
+++ b/include/uui/container.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <cstdlib>
+
+#include <iostream>
+#include <memory>
+#include <vector>
+
+#include "uui/config.hpp"
+
+namespace uui
+{
+class Component;
+class GlComponent;
+class Container
+{
+	friend class GlComponent;
+public:
+	enum Type
+	{
+		WINDOW,
+		FLEX,
+		STACK
+	};
+
+	Type type;
+
+protected:
+#ifdef DEBUG
+	constexpr static bool debug_mode = true;
+#else
+	constexpr static bool debug_mode = false;
+#endif
+	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;
+	virtual std::tuple<int, int> get_child_position(const std::size_t child_index [[maybe_unused]]) const = 0;
+};
+
+} // namespace uui
diff --git a/include/uui/flex.hpp b/include/uui/flex.hpp
new file mode 100644
index 0000000..1adf974
--- /dev/null
+++ b/include/uui/flex.hpp
@@ -0,0 +1,16 @@
+#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
new file mode 100644
index 0000000..e7126d6
--- /dev/null
+++ b/include/uui/font_manager.hpp
@@ -0,0 +1,56 @@
+#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, std::size_t font_size) = 0;
+};
+} // namespace uui
diff --git a/include/uui/label.hpp b/include/uui/label.hpp
new file mode 100644
index 0000000..2de7c22
--- /dev/null
+++ b/include/uui/label.hpp
@@ -0,0 +1,22 @@
+#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 bae5211..4860c89 100644
--- a/include/uui/opengl/application.hpp
+++ b/include/uui/opengl/application.hpp
@@ -1,21 +1,17 @@
 #pragma once
 
-#include <functional>
 #include <memory>
 #include <string>
-#include <variant>
 #include <vector>
 
 #include "graphic_context.hpp"
+#include "uui/application.hpp"
 #include "uui/config.hpp"
-#include "uui/opengl/container.hpp"
-#include "uui/opengl/font_manager.hpp"
 
 namespace uui
 {
-template<typename T> using InitFunction = const std::function<void(T&)>&;
 class GlWindow;
-class GlApplication
+class GlApplication final: virtual public Application
 {
 	friend class GlWindow;
 
@@ -28,69 +24,15 @@ public:
 	std::vector<std::shared_ptr<GlWindow>> windows;
 
 	GlApplication();
-	~GlApplication();
+	virtual ~GlApplication() final;
 
-	void run();
-	void create_window(int width, int height, const std::string& title, InitFunction<GlWindow> init);
-	std::shared_ptr<GlWindow> get_window(std::size_t index) const;
-
-private:
-	static GlApplication* application_pointer;
-};
-
-class GlComponent;
-class GlFlex;
-class GlLabel;
-class GlStack;
-class GlWindow: public GlContainer, public std::enable_shared_from_this<GlWindow>
-{
-	friend class GlApplication;
-	friend class GlComponent;
-	friend class GlFlex;
-	friend class GlLabel;
-	friend class GlStack;
-
-public:
-	std::string title;
-
-	GlWindow(const GlWindow&) = delete;
-	GlWindow(GlWindow&&) = delete;
-	~GlWindow();
-
-	void create_component(
-		const position_t x, const position_t y, const position_t width, const position_t height,
-		InitFunction<GlComponent> init);
-	void create_label(
-		const position_t x, const position_t y, const std::string& text,
-		const std::tuple<float, float, float, float>& text_color, InitFunction<GlLabel> init);
-	void create_flex(const position_t x, const position_t y, const Direction direction, InitFunction<GlFlex> init);
-	void create_stack(const position_t x, const position_t y, const Direction direction, InitFunction<GlStack> init);
+	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;
 
 protected:
-	GlApplication* app;
-	bool initialized;
-
-	int width;
-	int height;
-	bool render_needed;
-	bool resize_needed;
-	bool iconified;
-
-	GlFontManager font_manager;
-
-	GLFWwindow* glfw_window;
-	GLuint gl_program;
-
-	GlWindow(GlApplication* app, int width, int height, const std::string& title);
-	std::shared_ptr<GlWindow> getptr() { return shared_from_this(); }
-
-	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);
+	void init() final;
+	void deinit() final;
 };
 
 } // namespace uui
diff --git a/include/uui/opengl/component.hpp b/include/uui/opengl/component.hpp
index 135bbc5..223d154 100644
--- a/include/uui/opengl/component.hpp
+++ b/include/uui/opengl/component.hpp
@@ -4,17 +4,19 @@
 #include <memory>
 
 #include "graphic_context.hpp"
+#include "uui/opengl/component.hpp"
+#include "uui/container.hpp"
 #include "uui/config.hpp"
-#include "uui/opengl/container.hpp"
-#include "uui/style.hpp"
-#include "window.hpp"
+#include "uui/opengl/window.hpp"
 
 namespace uui
 {
 class GlFlex;
 class GlStack;
-class GlComponent: public std::enable_shared_from_this<GlComponent>
+class GlComponent: public std::enable_shared_from_this<GlComponent>, virtual public Component
 {
+	friend class Container;
+	friend class GlContainer;
 	friend class GlWindow;
 	friend class GlFlex;
 	friend class GlStack;
@@ -22,25 +24,10 @@ class GlComponent: public std::enable_shared_from_this<GlComponent>
 public:
 	virtual ~GlComponent();
 
-	void set_background_color(float r, float g, float b, float a = 1.0f);
+	void set_background_color(float r, float g, float b, float a = 1.0f) final;
 
 protected:
-	std::shared_ptr<GlWindow> window;
-	std::size_t window_index;
-	std::shared_ptr<GlContainer> parent;
-	std::size_t parent_index;
-
-	position_t position_x;
-	position_t position_y;
-	size_t size_width;
-	size_t size_height;
-	bool coord_all_relative;
-	Style style;
-
-	std::array<float, 4> background_color;
-
-	bool initialized;
-
+	std::shared_ptr<GlWindow> gl_window;
 	GLuint gl_vbo;
 	GLuint gl_vao;
 	GLuint gl_ebo;
@@ -52,16 +39,17 @@ protected:
 	GlComponent(
 		std::shared_ptr<GlWindow> window, std::size_t window_index, const position_t x, const position_t y,
 		const position_t width, const position_t height):
-		GlComponent(window, window_index, window, window_index, x, y, width, height)
+		GlComponent(window, window_index, std::static_pointer_cast<GlContainer>(window), window_index, x, y, width, height)
 	{}
 	GlComponent(const GlComponent&) = delete;
 	GlComponent(GlComponent&&) = default;
 	std::shared_ptr<GlComponent> getptr() { return shared_from_this(); }
 
+	virtual void render();
+
 	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
index 0772e6d..973059e 100644
--- a/include/uui/opengl/container.hpp
+++ b/include/uui/opengl/container.hpp
@@ -6,51 +6,29 @@
 #include <memory>
 #include <vector>
 
+#include "uui/container.hpp"
+#include "uui/component.hpp"
+
 namespace uui
 {
-class GlComponent;
-class GlFlex;
-class GlContainer
+class GlContainer: virtual public Container
 {
-	friend class GlComponent;
-	friend class GlFlex;
 
 protected:
 	GlContainer() = default;
 	GlContainer(const GlContainer&) = default;
 	GlContainer(GlContainer&&) = default;
 
-	virtual std::size_t push_child(std::shared_ptr<GlComponent> child)
-	{
-		components.push_back(child);
-		return components.size() - 1;
-	}
-	virtual std::shared_ptr<GlComponent> get_child(std::size_t index) const { return components.at(index); }
-	virtual void remove_child(std::size_t index) { components.at(index) = nullptr; };
+	virtual std::size_t push_child(std::shared_ptr<Component> child [[maybe_unused]]) final;
+	std::size_t push_child(std::shared_ptr<GlComponent> child);
+	std::shared_ptr<Component> get_child(std::size_t index) const final;
+	virtual void remove_child(std::size_t index) final;
+	virtual std::tuple<int, int> get_child_position(const std::size_t child_index [[maybe_unused]]) const override;
 
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index) const { return {0, 0}; }
+	std::vector<std::shared_ptr<GlComponent>> components;
 
 public:
-	#ifdef DEBUG
-	constexpr static bool debug_mode = true;
-	#else
-	constexpr static bool debug_mode = false;
-	#endif
-	enum Type
-	{
-		WINDOW,
-		FLEX,
-		STACK
-	};
-	std::vector<std::shared_ptr<GlComponent>> components;
-	Type type;
-
-	virtual ~GlContainer()
-	{
-		if constexpr(debug_mode)
-			std::cout << "Destroying Container" << std::endl;
-		components.clear();
-	}
+	~GlContainer();
 };
 
 } // namespace uui
diff --git a/include/uui/opengl/flex.hpp b/include/uui/opengl/flex.hpp
index 918792a..b73fac3 100644
--- a/include/uui/opengl/flex.hpp
+++ b/include/uui/opengl/flex.hpp
@@ -4,14 +4,14 @@
 #include <string>
 #include <tuple>
 
-#include "uui/opengl/component.hpp"
+#include "uui/flex.hpp"
 #include "uui/opengl/container.hpp"
-#include "uui/opengl/label.hpp"
 #include "uui/opengl/stack.hpp"
+#include "uui/opengl/window.hpp"
 
 namespace uui
 {
-class GlFlex: public GlStack
+class GlFlex: virtual public GlStack, virtual public Flex
 {
 	friend class GlWindow;
 
diff --git a/include/uui/opengl/font_manager.hpp b/include/uui/opengl/font_manager.hpp
index 926f84c..19d1ab7 100644
--- a/include/uui/opengl/font_manager.hpp
+++ b/include/uui/opengl/font_manager.hpp
@@ -7,56 +7,27 @@
 
 #include <ft2build.h>
 #include FT_FREETYPE_H
-#include "graphic_context.hpp"
+
+#include "uui/font_manager.hpp"
+#include "uui/opengl/graphic_context.hpp"
 
 namespace uui
 {
 class GlWindow;
-class GlFontManager
+class GlFontManager final: public FontManager
 {
 	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);
-	std::tuple<int, int> get_text_size(const std::string& text, Font& font, 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;
 
 private:
-	static constexpr int ATLAS_MAX_WIDTH = 1024;
-
-	bool initialized;
-
-	FT_Library ft;
-
 	GLuint gl_program;
 	GLuint gl_vao;
 	GLuint gl_vbo;
diff --git a/include/graphic_context.hpp b/include/uui/opengl/graphic_context.hpp
similarity index 78%
rename from include/graphic_context.hpp
rename to include/uui/opengl/graphic_context.hpp
index 800a70d..5837abc 100644
--- a/include/graphic_context.hpp
+++ b/include/uui/opengl/graphic_context.hpp
@@ -11,3 +11,8 @@
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
 // clang-format off
+
+namespace Config
+{
+	constexpr unsigned int FONT_TEXTURE_UNIT = GL_TEXTURE0;
+}
diff --git a/include/uui/opengl/label.hpp b/include/uui/opengl/label.hpp
index 99f094d..bbcb296 100644
--- a/include/uui/opengl/label.hpp
+++ b/include/uui/opengl/label.hpp
@@ -3,6 +3,7 @@
 #include <string>
 #include <tuple>
 
+#include "uui/label.hpp"
 #include "uui/opengl/component.hpp"
 #include "uui/opengl/container.hpp"
 
@@ -10,17 +11,12 @@ namespace uui
 {
 class GlFlex;
 class GlStack;
-class GlLabel: public GlComponent
+class GlLabel final: virtual public GlComponent, virtual public Label
 {
 	friend class GlWindow;
 	friend class GlFlex;
 	friend class GlStack;
 
-	std::size_t font_index;
-
-	float get_width() const;
-	float get_height() const;
-
 protected:
 	std::string text;
 	std::tuple<float, float, float, float> text_color;
@@ -38,7 +34,7 @@ protected:
 		GlLabel(window, window_index, window, window_index, x, y, text, text_color)
 	{}
 
-	void render();
+	void render() final;
 };
 
 } // namespace uui
diff --git a/include/uui/opengl/stack.hpp b/include/uui/opengl/stack.hpp
index b50dd3d..97d58de 100644
--- a/include/uui/opengl/stack.hpp
+++ b/include/uui/opengl/stack.hpp
@@ -6,24 +6,21 @@
 
 #include "uui/opengl/component.hpp"
 #include "uui/opengl/container.hpp"
-#include "uui/opengl/label.hpp"
+#include "uui/stack.hpp"
 
 namespace uui
 {
-class GlStack: public GlComponent, public GlContainer
+class GlStack: virtual public GlComponent, virtual public GlContainer, virtual public Stack
 {
 	friend class GlWindow;
 
 public:
-	void create_component(const position_t width, const position_t height, InitFunction<GlComponent> init);
+	void create_component(const position_t width, const position_t height, InitFunction<Component> init) override;
 	void create_label(
-		const std::string& text, const std::tuple<float, float, float, float>& text_color, InitFunction<GlLabel> init);
+		const std::string& text, const std::tuple<float, float, float, float>& text_color,
+		InitFunction<Label> init) override;
 
 protected:
-	Direction direction;
-	int content_width;
-	int content_height;
-
 	GlStack(
 		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);
@@ -33,10 +30,7 @@ protected:
 		GlStack(window, window_index, window, window_index, x, y, direction)
 	{}
 
-	float get_width() const;
-	float get_height() const;
-
-	virtual std::tuple<int, int> get_child_position(const std::size_t child_index) const;
+	std::tuple<int, int> get_child_position(const std::size_t child_index) const override;
 };
 
 } // namespace uui
diff --git a/include/uui/opengl/uui.hpp b/include/uui/opengl/uui.hpp
deleted file mode 100644
index f579f95..0000000
--- a/include/uui/opengl/uui.hpp
+++ /dev/null
@@ -1,6 +0,0 @@
-#pragma once
-
-#include "uui/opengl/application.hpp"
-#include "uui/opengl/component.hpp"
-#include "uui/opengl/flex.hpp"
-#include "uui/opengl/label.hpp"
diff --git a/include/uui/opengl/window.hpp b/include/uui/opengl/window.hpp
index dd3f0d0..0e04afd 100644
--- a/include/uui/opengl/window.hpp
+++ b/include/uui/opengl/window.hpp
@@ -1,3 +1,57 @@
 #pragma once
 
+#include "uui/config.hpp"
 #include "uui/opengl/application.hpp"
+#include "uui/opengl/container.hpp"
+#include "uui/opengl/font_manager.hpp"
+#include "uui/window.hpp"
+
+namespace uui
+{
+class GlComponent;
+class GlContainer;
+class GlFlex;
+class GlLabel;
+class GlStack;
+class GlWindow final: public std::enable_shared_from_this<GlWindow>, virtual public Window, virtual public GlContainer
+{
+	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 position_t x, const position_t y, const position_t width, const position_t height,
+		InitFunction<Component> init) final;
+	void create_label(
+		const position_t x, const position_t y, const std::string& text,
+		const std::tuple<float, float, float, float>& text_color, InitFunction<Label> init) final;
+	void create_flex(const position_t x, const position_t y, const Direction direction, InitFunction<Flex> init) final;
+	void create_stack(
+		const position_t x, const position_t y, const Direction direction, 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);
+};
+} // namespace uui
diff --git a/include/uui/stack.hpp b/include/uui/stack.hpp
new file mode 100644
index 0000000..bc3d015
--- /dev/null
+++ b/include/uui/stack.hpp
@@ -0,0 +1,27 @@
+#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 position_t width, const position_t height, InitFunction<Component> init) = 0;
+	virtual void create_label(
+		const std::string& text, const std::tuple<float, float, float, float>& text_color,
+		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/uui.hpp b/include/uui/uui.hpp
new file mode 100644
index 0000000..0c04834
--- /dev/null
+++ b/include/uui/uui.hpp
@@ -0,0 +1,9 @@
+#pragma once
+
+#include "uui/application.hpp"
+#include "uui/config.hpp"
+#include "uui/component.hpp"
+#include "uui/flex.hpp"
+#include "uui/label.hpp"
+#include "uui/stack.hpp"
+#include "uui/window.hpp"
diff --git a/include/uui/window.hpp b/include/uui/window.hpp
index b5d6c49..7cc52d5 100644
--- a/include/uui/window.hpp
+++ b/include/uui/window.hpp
@@ -4,21 +4,56 @@
 #include <string>
 #include <vector>
 
-#include "graphic_context.hpp"
-#include "uui/component.hpp"
+#include "uui/application.hpp"
+#include "uui/config.hpp"
+#include "uui/container.hpp"
+#include "uui/font_manager.hpp"
 
 namespace uui
 {
-class Window
+class Component;
+class Label;
+class Flex;
+class Stack;
+class Window: virtual public Container
 {
+	friend class Component;
+
 public:
 	std::string title;
 
-	virtual void add_component(const Component& box) = 0;
+	std::shared_ptr<FontManager> font_manager;
+
+	virtual void create_component(
+		const position_t x, const position_t y, const position_t width, const position_t height,
+		InitFunction<Component> init) = 0;
+	virtual void create_label(
+		const position_t x, const position_t y, const std::string& text,
+		const std::tuple<float, float, float, float>& text_color, InitFunction<Label> init) = 0;
+	virtual void create_flex(
+		const position_t x, const position_t y, const Direction direction, InitFunction<Flex> init) = 0;
+	virtual void create_stack(
+		const position_t x, const position_t y, const Direction direction, InitFunction<Stack> init) = 0;
+
+	int width() { return _width; };
+	int height() { return _height; };
 
 protected:
-	GLFWwindow* glfw_window;
+#ifdef DEBUG
+	constexpr static bool debug_mode = true;
+#else
+	constexpr static bool debug_mode = false;
+#endif
 
-	virtual void draw() = 0;
+	std::shared_ptr<Application> _app;
+	bool _initialized;
+
+	int _width;
+	int _height;
+	bool _render_needed;
+	bool _resize_needed;
+	bool _iconified;
+
+	virtual void render() = 0;
 };
 } // namespace uui
diff --git a/make.py b/make.py
index 2a627af..d15832c 100644
--- a/make.py
+++ b/make.py
@@ -20,7 +20,7 @@ class Config:
 
     COMMON_FLAGS = '-std=c++17 -fno-semantic-interposition'
     COMMON_DEBUG_FLAGS = '-g -Og -DDEBUG'
-    COMMON_RELEASE_FLAGS = '-O2 -flto'
+    COMMON_RELEASE_FLAGS = '-O2 -flto=auto'
     COMPILE_FLAGS = f'-Wall -Wextra -Wpedantic -Wconversion -I{INCLUDE_DIR} `pkg-config --cflags glfw3 vulkan gl x11 freetype2`'
     LINK_FLAGS = '-lpthread -ldl `pkg-config --libs glfw3 vulkan gl x11 freetype2`'
 
diff --git a/src/test/benchmark_text.cpp b/src/test/benchmark_text.cpp
index dccd7a5..24eeffa 100644
--- a/src/test/benchmark_text.cpp
+++ b/src/test/benchmark_text.cpp
@@ -1,6 +1,6 @@
 #include <iostream>
 
-#include "uui/opengl/uui.hpp"
+#include "uui/uui.hpp"
 
 using namespace std;
 
@@ -8,12 +8,12 @@ int main()
 {
 	try
 	{
-		uui::GlApplication app;
-		// uui::GlApplication app2; // exception : application already created
-		app.create_window(800, 600, "OpenGl!", [](uui::GlWindow& window) {
+		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) {
 			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();
+		app->run();
 	}
 	catch(const std::exception& error)
 	{
diff --git a/src/test/example_gl.cpp b/src/test/example_gl.cpp
index 169d5dd..65650cf 100644
--- a/src/test/example_gl.cpp
+++ b/src/test/example_gl.cpp
@@ -1,6 +1,6 @@
 #include <iostream>
 
-#include "uui/opengl/uui.hpp"
+#include "uui/uui.hpp"
 
 using namespace std;
 
@@ -10,92 +10,92 @@ int main()
 	{
 		cout << "Starting example 1" << endl;
 		{
-			uui::GlApplication app;
-			// uui::GlApplication app2; // exception : application already created
-			app.create_window(800, 600, "OpenGl!", [](uui::GlWindow& window) {
-				window.create_component(0, 100, 0.5f, 50, [](uui::GlComponent& component) {
+			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(0, 100, 0.5f, 50, [](uui::Component& component) {
 					component.set_background_color(0.8f, 0.1f, 0.5f);
 				});
 
-				window.create_component(0.25f, 50, 0.4f, 150, [](uui::GlComponent& component) {
+				window.create_component(0.25f, 50, 0.4f, 150, [](uui::Component& component) {
 					component.set_background_color(0.3f, 0.8f, 0.4f, 0.5f);
 				});
 
-				window.create_label(50, 50, "Hello World!", {0.5f, 1.0f, 0.5f, 1.0f}, [](uui::GlLabel& label) {
+				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, 0.8f);
 				});
 
-				window.create_label(0.5f, 0.5f, "Hello World!", {1.0f, 1.0f, 1.0f, 0.5f}, [](uui::GlLabel& label) {
+				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::GlFlex& flex) {
-					flex.create_component(100, 50, [](uui::GlComponent& component) {
+				window.create_flex(200, 0.6f, uui::Direction::HORIZONTAL, [](uui::Flex& flex) {
+					flex.create_component(100, 50, [](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::GlComponent& component) {
+					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::GlFlex& flex) {
-					flex.create_component(50, 100, [](uui::GlComponent& component) {
+				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::GlComponent& component) {
+					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::GlWindow& window) {
-				window.create_stack(200, 0.6f, uui::Direction::HORIZONTAL, [](uui::GlStack& stack) {
-					stack.create_component(100, 50, [](uui::GlComponent& component) {
+			app->create_window(800, 600, "OpenGl 2", [](uui::Window& window) {
+				window.create_stack(200, 0.6f, uui::Direction::HORIZONTAL, [](uui::Stack& stack) {
+					stack.create_component(100, 50, [](uui::Component& component) {
 						component.set_background_color(0.2f, 0.75f, 0.25f);
 					});
 					stack.create_label("test", {0.8f, 0.2f, 0.2f, 1.0f}, {});
-					stack.create_component(100, 20, [](uui::GlComponent& component) {
+					stack.create_component(100, 20, [](uui::Component& component) {
 						component.set_background_color(0.2f, 0.25f, 0.75f);
 					});
 				});
 
-				window.create_stack(50, 400, uui::Direction::VERTICAL, [](uui::GlStack& stack) {
-					stack.create_component(100, 50, [](uui::GlComponent& component) {
+				window.create_stack(50, 400, uui::Direction::VERTICAL, [](uui::Stack& stack) {
+					stack.create_component(100, 50, [](uui::Component& component) {
 						component.set_background_color(0.2f, 0.75f, 0.25f);
 					});
 					stack.create_label("test", {0.8f, 0.2f, 0.2f, 1.0f}, {});
-					stack.create_component(100, 20, [](uui::GlComponent& component) {
+					stack.create_component(100, 20, [](uui::Component& component) {
 						component.set_background_color(0.2f, 0.25f, 0.75f);
 					});
 				});
 			});
 
-			app.run();
+			app->run();
 		}
 		cout << "\nStarting example 2" << endl;
 		{
-			uui::GlApplication app;
-			app.create_window(800, 600, "OpenGl!", [](uui::GlWindow& window) {
-				window.create_component(0.25f, 0.25f, 0.5f, 0.5f, [](uui::GlComponent& component) {
+			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::GlComponent& component) {
+				window.create_component(0.75f, 0.75f, 0.25f, 0.25f, [](uui::Component& component) {
 					component.set_background_color(0.2f, 0.1f, 0.5f);
 				});
 			});
 
-			app.create_window(600, 600, "OpenGL 2!", [](uui::GlWindow& window) {
-				window.create_component(0, 0.5f, 100, 0.5f, [](uui::GlComponent& component) {
+			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::GlLabel& label) {
+				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();
+			app->run();
 		}
 	}
 	catch(const std::exception& error)
diff --git a/src/test/sample.cpp b/src/test/sample.cpp
index 345a3e6..5f8b2d6 100644
--- a/src/test/sample.cpp
+++ b/src/test/sample.cpp
@@ -1,14 +1,26 @@
-#include "uui/opengl/uui.hpp"
+#include "uui/uui.hpp"
 
 int main()
 {
-	uui::GlApplication app;
-	app.create_window(800, 600, "UUI sample", [](uui::GlWindow& window) {
+	auto app = uui::create_application(uui::Application::OPENGL);
+	app->create_window(800, 600, "UUI sample", [](uui::Window& window) {
 		window.create_component(
-			0, 0, 200, 100, [](uui::GlComponent& component) { component.set_background_color(1.0f, 0.f, 0.f, 0.5f); });
+			0, 0, 200, 100, [](uui::Component& component) { component.set_background_color(1.0f, 0.f, 0.f, 0.5f); });
 		window.create_label(0.5f, 0.5f, "Hello world!", {0.8f, 0.8f, 0.8f, 1.0f}, nullptr);
 	});
-	app.run();
+	app->run();
+	// app->run();
+
+	// app = uui::create_application(uui::Application::OPENGL);
+	// app->create_window(800, 600, "test", [](uui::Window& window) {
+	// 	window.create_flex(10, 10, uui::HORIZONTAL, [](uui::Flex& flex) {
+	// 		flex.create_label("Hello!", {0.5f, 0.f, 0.f, 1.0f}, [](uui::Label& label) {
+	// 			label.set_background_color(0.2f, 0.2f, 0.6f, 1.0f);
+	// 		});
+	// 		flex.create_label("World!", {1.0, 1.0, 1.0, 1.0}, {});
+	// 	});
+	// });
+	// app->run();
 
 	return 0;
 }
diff --git a/src/uui/application.cpp b/src/uui/application.cpp
index 84209ca..368eb79 100644
--- a/src/uui/application.cpp
+++ b/src/uui/application.cpp
@@ -1,3 +1,20 @@
 #include "uui/application.hpp"
 
-bool uui::Application::application_created = false;
+#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;
+	}
+}
diff --git a/src/uui/opengl/application.cpp b/src/uui/opengl/application.cpp
index b3b3178..1fc5879 100644
--- a/src/uui/opengl/application.cpp
+++ b/src/uui/opengl/application.cpp
@@ -3,16 +3,32 @@
 #include <chrono>
 #include <iostream>
 
-uui::GlApplication* uui::GlApplication::application_pointer = nullptr;
+#include "uui/opengl/window.hpp"
 
 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
 	glfwInit();
 	// Set all the required options for GLFW
@@ -23,22 +39,24 @@ uui::GlApplication::GlApplication()
 	if constexpr(uui::GlApplication::debug_mode)
 		glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, true);
 
-	application_pointer = this;
+	initialized = true;
 }
 
-uui::GlApplication::~GlApplication()
+void uui::GlApplication::deinit()
 {
 	if constexpr(debug_mode)
-		std::cout << "Destroying the GlApplication" << std::endl;
+		std::cout << "Deinit the GlApplication" << std::endl;
 	windows.clear();
 	glfwTerminate();
-	application_pointer = nullptr;
+	initialized = false;
 }
 
 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;
@@ -75,6 +93,8 @@ 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;
@@ -85,7 +105,7 @@ void uui::GlApplication::run()
 					window->render();
 				else
 				{
-					if(window->render_needed && !window->iconified)
+					if(window->_render_needed && !window->_iconified)
 						window->render();
 				}
 			}
@@ -95,12 +115,12 @@ 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<GlWindow> init)
+void uui::GlApplication::create_window(int width, int height, const std::string& title, uui::InitFunction<Window> init)
 {
-	std::shared_ptr<uui::GlWindow> window(new uui::GlWindow(this, width, height, title));
+	auto window = std::shared_ptr<uui::GlWindow>(new uui::GlWindow(current_application, width, height, title));
 	window->init();
 	windows.push_back(window);
 	glfwSwapInterval(1);
@@ -114,7 +134,7 @@ void uui::GlApplication::create_window(
 		init(*window);
 }
 
-std::shared_ptr<uui::GlWindow> uui::GlApplication::get_window(std::size_t index) const
+std::shared_ptr<uui::Window> uui::GlApplication::get_window(std::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 07fb49d..280fd12 100644
--- a/src/uui/opengl/component.cpp
+++ b/src/uui/opengl/component.cpp
@@ -3,17 +3,30 @@
 #include <iostream>
 
 #include "uui/opengl/application.hpp"
+#include "uui/opengl/container.hpp"
 #include "uui/opengl/gl_utils.hpp"
 
 uui::GlComponent::GlComponent(
-	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 position_t width, const position_t height):
-	window(window),
-	window_index(window_index), parent(parent), parent_index(parent_index), position_x(x), position_y(y),
-	size_width(width), size_height(height), initialized(false)
+	std::shared_ptr<uui::GlWindow> window, std::size_t window_index, std::shared_ptr<uui::GlContainer> parent,
+	std::size_t parent_index, const position_t x, const position_t y, const position_t width, const position_t height)
 {
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating a GlBox" << std::endl;
+	if constexpr(debug_mode)
+		std::cout << "Creating a GlComponent " << parent_index << std::endl;
+
+	gl_window = window;
+	this->window = std::static_pointer_cast<uui::Window>(window);
+
+	this->window_index = window_index;
+	this->parent = parent;
+	this->parent_index = parent_index;
+	this->parent_index = parent_index;
+
+	initialized = false;
+
+	position_x = x;
+	position_y = y;
+	size_width = width;
+	size_height = height;
 
 	coord_all_relative = true;
 	auto parse_coords = [&](position_t& value) {
@@ -36,7 +49,7 @@ uui::GlComponent::GlComponent(
 uui::GlComponent::~GlComponent()
 {
 	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Closing a GlComponent" << std::endl;
+		std::cout << "Destructor GlComponent " << parent_index << std::endl;
 	if(initialized)
 		deinit();
 	// if(parent != window)
@@ -54,7 +67,7 @@ void uui::GlComponent::set_background_color(float r, float g, float b, float a /
 void uui::GlComponent::init()
 {
 	if(initialized)
-		throw std::runtime_error("GlBox error : calling init while already initialized");
+		throw std::runtime_error("GlComponent error : calling init while already initialized");
 
 	glGenVertexArrays(1, &gl_vao);
 	glGenBuffers(1, &gl_vbo);
@@ -88,16 +101,16 @@ 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);
+		: 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);
+		: 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);
+		: 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);
+		: 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;
@@ -136,12 +149,18 @@ void uui::GlComponent::set_vbo_data()
 
 void uui::GlComponent::deinit()
 {
+	if constexpr(uui::GlApplication::debug_mode)
+		std::cout << "Deinit GlComponent " << parent_index << std::endl;
+
 	if(!initialized)
-		throw std::runtime_error("GlBox error : calling deinit while not initialized");
+		throw std::runtime_error("GlComponent error : calling deinit while not initialized");
 
 	glDeleteVertexArrays(1, &gl_vao);
 	glDeleteBuffers(1, &gl_vbo);
 	glDeleteBuffers(1, &gl_ebo);
+
+	window = nullptr;
+	parent = nullptr;
 	initialized = false;
 }
 
diff --git a/src/uui/opengl/container.cpp b/src/uui/opengl/container.cpp
new file mode 100644
index 0000000..c9d0242
--- /dev/null
+++ b/src/uui/opengl/container.cpp
@@ -0,0 +1,37 @@
+#include "uui/opengl/container.hpp"
+
+#include "uui/opengl/component.hpp"
+
+std::size_t uui::GlContainer::push_child(std::shared_ptr<uui::Component> child [[maybe_unused]])
+{
+	throw std::runtime_error("GlContainer error : should only push GlComponent child, not Component");
+}
+
+std::size_t uui::GlContainer::push_child(std::shared_ptr<uui::GlComponent> child)
+{
+	components.push_back(child);
+	// components.push_back(std::static_pointer_cast<uui::Component>(child));
+	return components.size() - 1;
+}
+
+std::shared_ptr<uui::Component> uui::GlContainer::get_child(std::size_t index) const
+{
+	return components.at(index);
+}
+
+void uui::GlContainer::remove_child(std::size_t index)
+{
+	components.at(index) = nullptr;
+};
+
+std::tuple<int, int> uui::GlContainer::get_child_position(const std::size_t child_index [[maybe_unused]]) const
+{
+	return {0, 0};
+}
+
+uui::GlContainer::~GlContainer()
+{
+	if constexpr(debug_mode)
+		std::cout << "Destroying GlContainer" << std::endl;
+	components.clear();
+}
diff --git a/src/uui/opengl/flex.cpp b/src/uui/opengl/flex.cpp
index bd259a2..73c9d55 100644
--- a/src/uui/opengl/flex.cpp
+++ b/src/uui/opengl/flex.cpp
@@ -7,10 +7,11 @@
 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 position_t x, const position_t y, const Direction direction):
+	GlComponent(window, window_index, parent, parent_index, x, y, 0.0f, 0.0f),
 	GlStack(window, window_index, parent, parent_index, x, y, direction)
 {
 	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating a GlStack" << std::endl;
+		std::cout << "Creating a GlFlex " << parent_index << std::endl;
 
 	type = Type::FLEX;
 	coord_all_relative = false;
@@ -20,10 +21,10 @@ std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_ind
 {
 	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));
+		: 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));
+		: static_cast<int>(std::get<1>(position_y) * static_cast<float>(window->height()));
 
 	if(child_index == 0)
 		return {initial_x, initial_y};
@@ -37,11 +38,11 @@ std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_ind
 		{
 			auto& component = components[index];
 			if(component->size_width.index() == 1)
-				width = static_cast<int>(std::get<1>(component->size_width) * static_cast<float>(window->width));
+				width = static_cast<int>(std::get<1>(component->size_width) * static_cast<float>(window->width()));
 			else
 				width = std::get<0>(component->size_width);
 			if(component->size_height.index() == 1)
-				height = static_cast<int>(std::get<1>(component->size_height) * static_cast<float>(window->height));
+				height = static_cast<int>(std::get<1>(component->size_height) * static_cast<float>(window->height()));
 			else
 				height = std::get<0>(component->size_height);
 		}
@@ -64,7 +65,7 @@ std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_ind
 			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)
+			if(x != initial_x && x + child_width > window->width())
 			{
 				x = initial_x + child_width;
 				y += max_height;
@@ -76,7 +77,7 @@ std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_ind
 		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)
+			if(x != initial_x && x + child_width > window->width())
 			{
 				x = initial_x;
 				y += max_height;
@@ -98,7 +99,7 @@ std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_ind
 			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)
+			if(y != initial_y && y + child_height > window->height())
 			{
 				y = initial_y + child_height;
 				x += max_width;
@@ -110,7 +111,7 @@ std::tuple<int, int> uui::GlFlex::get_child_position(const std::size_t child_ind
 		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)
+			if(y != initial_y && y + child_height > window->height())
 			{
 				y = initial_y;
 				x += max_width;
diff --git a/src/uui/opengl/font_manager.cpp b/src/uui/opengl/font_manager.cpp
index 554c83d..6e66b2a 100644
--- a/src/uui/opengl/font_manager.cpp
+++ b/src/uui/opengl/font_manager.cpp
@@ -11,7 +11,10 @@
 #include "uui/opengl/gl_utils.hpp"
 #include "uui/shader.hpp"
 
-uui::GlFontManager::GlFontManager(): initialized(false) {}
+uui::GlFontManager::GlFontManager()
+{
+	initialized = false;
+}
 
 uui::GlFontManager::~GlFontManager()
 {
@@ -25,7 +28,7 @@ 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");
@@ -117,6 +120,9 @@ 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);
diff --git a/src/uui/opengl/label.cpp b/src/uui/opengl/label.cpp
index c776be1..88fc169 100644
--- a/src/uui/opengl/label.cpp
+++ b/src/uui/opengl/label.cpp
@@ -2,6 +2,7 @@
 
 #include <iostream>
 
+#include "uui/opengl/font_manager.hpp"
 #include "uui/opengl/gl_utils.hpp"
 
 uui::GlLabel::GlLabel(
@@ -11,12 +12,12 @@ uui::GlLabel::GlLabel(
 	GlComponent(window, window_index, parent, parent_index, x, y, 0.0f, 0.0f),
 	text(text), text_color(text_color)
 {
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating a GlLabel" << std::endl;
+	if constexpr(debug_mode)
+		std::cout << "Creating GlLabel " << parent_index << 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);
+		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;
@@ -24,15 +25,15 @@ uui::GlLabel::GlLabel(
 
 void uui::GlLabel::render()
 {
-	float text_x = position_x.index() == 1 ? std::get<1>(position_x) * static_cast<float>(window->width)
+	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)
+	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
index 8ee1a83..cc3a40e 100644
--- a/src/uui/opengl/stack.cpp
+++ b/src/uui/opengl/stack.cpp
@@ -3,34 +3,36 @@
 #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 position_t x, const position_t y, const Direction direction):
-	GlComponent(window, window_index, parent, parent_index, x, y, 0.0f, 0.0f),
-	direction(direction)
+	GlComponent(window, window_index, parent, parent_index, x, y, 0.0f, 0.0f)
 {
 	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating a GlStack" << std::endl;
+		std::cout << "Creating GlStack " << parent_index << std::endl;
+
+	this->direction = direction;
 
 	type = Type::STACK;
 	coord_all_relative = false;
 }
 
 void uui::GlStack::create_component(
-	const uui::position_t width, const uui::position_t height, uui::InitFunction<uui::GlComponent> init)
+	const uui::position_t width, const uui::position_t height, uui::InitFunction<uui::Component> init)
 {
 	if(!initialized)
 		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
 
-	glfwMakeContextCurrent(window->glfw_window);
+	glfwMakeContextCurrent(gl_window->glfw_window);
 	std::shared_ptr<uui::GlComponent> component(new uui::GlComponent(
-		window, window->components.size(), std::dynamic_pointer_cast<uui::GlContainer>(shared_from_this()),
+		gl_window, gl_window->components.size(), std::dynamic_pointer_cast<uui::GlContainer>(shared_from_this()),
 		components.size(), 0, 0, width, height));
 	push_child(component);
 	component->init();
 	std::tie(component->position_x, component->position_y) = get_child_position(components.size() - 1);
-	window->components.push_back(component);
+	gl_window->components.push_back(component);
 
 	if(component != nullptr)
 		init(*component);
@@ -38,19 +40,19 @@ void uui::GlStack::create_component(
 
 void uui::GlStack::create_label(
 	const std::string& text, const std::tuple<float, float, float, float>& text_color,
-	uui::InitFunction<uui::GlLabel> init)
+	uui::InitFunction<uui::Label> init)
 {
 	if(!initialized)
 		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
 
-	glfwMakeContextCurrent(window->glfw_window);
+	glfwMakeContextCurrent(gl_window->glfw_window);
 	std::shared_ptr<uui::GlLabel> label(new uui::GlLabel(
-		window, window->components.size(), std::dynamic_pointer_cast<uui::GlContainer>(shared_from_this()),
+		gl_window, gl_window->components.size(), std::dynamic_pointer_cast<uui::GlContainer>(shared_from_this()),
 		components.size(), 0, 0, text, text_color));
-	push_child(label);
+	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);
-	window->components.push_back(label);
+	gl_window->components.push_back(label);
 
 	if(label != nullptr && init != nullptr)
 		init(*label);
@@ -59,9 +61,9 @@ void uui::GlStack::create_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));
+									: 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));
+									: static_cast<int>(std::get<1>(position_y) * static_cast<float>(window->height()));
 
 	if(child_index == 0)
 		return {x, y};
@@ -75,7 +77,7 @@ std::tuple<int, int> uui::GlStack::get_child_position(const std::size_t child_in
 			{
 				auto& component = components[index];
 				if(component->size_width.index() == 1)
-					x += static_cast<int>(std::get<1>(component->size_width) * static_cast<float>(window->width));
+					x += static_cast<int>(std::get<1>(component->size_width) * static_cast<float>(window->width()));
 				else
 					x += std::get<0>(component->size_width);
 			}
@@ -88,7 +90,7 @@ std::tuple<int, int> uui::GlStack::get_child_position(const std::size_t child_in
 			{
 				auto& component = components[index];
 				if(component->size_height.index() == 1)
-					y += static_cast<int>(std::get<1>(component->size_height) * static_cast<float>(window->height));
+					y += static_cast<int>(std::get<1>(component->size_height) * static_cast<float>(window->height()));
 				else
 					y += std::get<0>(component->size_height);
 			}
diff --git a/src/uui/opengl/window.cpp b/src/uui/opengl/window.cpp
index 89c5e31..096a226 100644
--- a/src/uui/opengl/window.cpp
+++ b/src/uui/opengl/window.cpp
@@ -6,11 +6,13 @@
 #include "uui/opengl/flex.hpp"
 #include "uui/opengl/gl_utils.hpp"
 #include "uui/opengl/label.hpp"
+#include "uui/opengl/flex.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, const char* message,
-	const void* userParam)
+	GLenum source, GLenum type, unsigned int id, GLenum severity, GLsizei length [[maybe_unused]], const char* message,
+	const void* userParam [[maybe_unused]])
 {
 	// ignore non-significant error/warning codes
 	if(id == 131169 || id == 131185 || id == 131218 || id == 131204)
@@ -59,59 +61,68 @@ 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->font_manager.gl_program);
+	glUseProgram(gl_window->gl_font_manager->gl_program);
 	glUniformMatrix4fv(
-		glGetUniformLocation(gl_window->font_manager.gl_program, "projection"), 1, GL_FALSE,
+		glGetUniformLocation(gl_window->gl_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, int action, int mods)
+void uui::GlWindow::glfw_key_callback(GLFWwindow* window, int key, int scancode [[maybe_unused]], int action, int mods [[maybe_unused]])
 {
 	if(key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
 		glfwSetWindowShouldClose(window, true);
 }
 
-uui::GlWindow::GlWindow(uui::GlApplication* app, int width, int height, const std::string& title):
-	app(app), initialized(false), width(width), height(height), render_needed(true), resize_needed(false),
-	iconified(false)
+uui::GlWindow::GlWindow(std::shared_ptr<uui::Application> app, int width, int height, const std::string& title)
 {
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Creating a GlWindow" << std::endl;
+	_app = app;
+	_initialized = false;
+	_width = width;
+	_height = height;
+	_render_needed = true;
+	_resize_needed = false;
+	_iconified = false;
+
+	if constexpr(debug_mode)
+		std::cout << "Creating GlWindow : " << title << std::endl;
 	this->title = title;
 	type = Type::WINDOW;
 }
 
 uui::GlWindow::~GlWindow()
 {
-	if constexpr(uui::GlApplication::debug_mode)
-		std::cout << "Closing a GlWindow" << std::endl;
-	if(initialized)
+	if constexpr(debug_mode)
+		std::cout << "Destructor GlWindow : " << title << std::endl;
+	if(_initialized)
 	{
-		if constexpr(uui::GlApplication::debug_mode)
-			std::cout << "Destructor-deinit a GlWindow" << std::endl;
+		if constexpr(debug_mode)
+			std::cout << "Destructor-deinit GlWindow : " << title << std::endl;
 		deinit();
 	}
 }
 
 void uui::GlWindow::init()
 {
-	if(initialized)
+	if(_initialized)
 		throw std::runtime_error("GlWindow error : calling init while already initialized");
 
-	glfw_window = glfwCreateWindow(width, height, title.c_str(), NULL, NULL);
+	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);
 	if(glfw_window == NULL)
 		throw std::runtime_error("GLWindow : failed to create GLFW window");
 	glfwMakeContextCurrent(glfw_window);
@@ -207,32 +218,35 @@ void uui::GlWindow::init()
 	glDeleteShader(vertex_shader);
 	glDeleteShader(fragment_shader);
 
-	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);
+	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(font_manager.gl_program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
+		glGetUniformLocation(gl_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 a GlWindow" << std::endl;
+		std::cout << "Deinit GlWindow : " << title << std::endl;
 
 	glfwMakeContextCurrent(glfw_window);
 	glDeleteProgram(gl_program);
-	for(auto& component: components) component->deinit();
+	for(auto& gl_component: components) gl_component->deinit();
 	components.clear();
-	font_manager.deinit();
+	gl_font_manager->deinit();
 	glfwDestroyWindow(glfw_window);
 
-	initialized = false;
+	_app = nullptr;
+	font_manager = nullptr;
+	gl_font_manager = nullptr;
+	_initialized = false;
 }
 
 void uui::GlWindow::render()
@@ -242,22 +256,22 @@ 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::position_t x, const uui::position_t y, const uui::position_t width, const uui::position_t height,
-	uui::InitFunction<GlComponent> init)
+	uui::InitFunction<Component> init)
 {
-	if(!initialized)
+	if(!_initialized)
 		throw std::runtime_error("GlWindow error : cannot create component while not initialized");
 
 	glfwMakeContextCurrent(glfw_window);
@@ -272,15 +286,15 @@ void uui::GlWindow::create_component(
 
 void uui::GlWindow::create_label(
 	const uui::position_t x, const uui::position_t y, const std::string& text,
-	const std::tuple<float, float, float, float>& text_color, uui::InitFunction<GlLabel> init)
+	const std::tuple<float, float, float, float>& text_color, uui::InitFunction<Label> init)
 {
-	if(!initialized)
+	if(!_initialized)
 		throw std::runtime_error("GlWindow error : cannot create label while not initialized");
 
 	glfwMakeContextCurrent(glfw_window);
 	std::shared_ptr<uui::GlLabel> label(
 		new uui::GlLabel(shared_from_this(), components.size(), x, y, text, text_color));
-	push_child(label);
+	push_child(std::static_pointer_cast<uui::GlComponent>(label));
 	label->init();
 
 	if(label != nullptr && init != nullptr)
@@ -288,14 +302,14 @@ void uui::GlWindow::create_label(
 }
 
 void uui::GlWindow::create_flex(
-	const uui::position_t x, const uui::position_t y, const uui::Direction direction, uui::InitFunction<GlFlex> init)
+	const uui::position_t x, const uui::position_t y, const uui::Direction direction, uui::InitFunction<Flex> init)
 {
-	if(!initialized)
+	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(), x, y, direction));
-	push_child(flex);
+	push_child(std::static_pointer_cast<uui::GlComponent>(flex));
 	flex->init();
 
 	if(flex != nullptr && init != nullptr)
@@ -303,16 +317,17 @@ void uui::GlWindow::create_flex(
 }
 
 void uui::GlWindow::create_stack(
-	const uui::position_t x, const uui::position_t y, const uui::Direction direction, uui::InitFunction<GlStack> init)
+	const uui::position_t x, const uui::position_t y, const uui::Direction direction, uui::InitFunction<Stack> init)
 {
-	if(!initialized)
+	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(), x, y, direction));
-	push_child(stack);
+	push_child(std::static_pointer_cast<uui::GlComponent>(stack));
 	stack->init();
 
 	if(stack != nullptr && init != nullptr)
 		init(*stack);
 }
+
diff --git a/umake b/umake
index f5965cc..797d6ac 160000
--- a/umake
+++ b/umake
@@ -1 +1 @@
-Subproject commit f5965cc91e7eb27d1def78113301e7ec28fad54a
+Subproject commit 797d6accd2fd4fd1faa742a6ec8039b6aad8d861