Tables: TableSetupColumn() user id uses ImGuiID as intended (typedef ImU32). internals: added GetCurrentTable(), LeftMostEnabledColumn. Demo/docs tweaks.

docs/BACKENDS.md

@@ -9,13 +9,13 @@ your application or engine to easily integrate Dear ImGui.** Each backend is typ
   e.g. Windows ([imgui_impl_win32.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_win32.cpp)), GLFW ([imgui_impl_glfw.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_glfw.cpp)), SDL2 ([imgui_impl_sdl.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_sdl.cpp)), etc.
 
 - The 'Renderer' backends are in charge of: creating atlas texture, rendering imgui draw data.<BR>
-  e.g. DirectX11 ([imgui_impl_dx11.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_dx11.cpp)), OpenGL/WebGL ([imgui_impl_opengl3.cpp]((https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_opengl3.cpp)), Vulkan ([imgui_impl_vulkan.cpp]((https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_vulkan.cpp)), etc.
+  e.g. DirectX11 ([imgui_impl_dx11.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_dx11.cpp)), OpenGL/WebGL ([imgui_impl_opengl3.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_opengl3.cpp), Vulkan ([imgui_impl_vulkan.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_vulkan.cpp), etc.
 
 - For some high-level frameworks, a single backend usually handle both 'Platform' and 'Renderer' parts.<BR>
   e.g. Allegro 5 ([imgui_impl_allegro5.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_allegro5.cpp)), Marmalade ([imgui_impl_marmalade.cpp](https://github.com/ocornut/imgui/blob/master/backends/imgui_impl_marmalade.cpp)). If you end up creating a custom backend for your engine, you may want to do the same.
 
 An application usually combines 1 Platform backend + 1 Renderer backend + main Dear ImGui sources.
-For example, the [example_win32_directx11](https://github.com/ocornut/imgui/tree/master/examples/example_win32_directx11) application combines imgui_impl_win32.cpp + imgui_impl_dx11.cpp. See [EXAMPLES.MD](https://github.com/ocornut/imgui/blob/master/docs/EXAMPLES.md) for details.
+For example, the [example_win32_directx11](https://github.com/ocornut/imgui/tree/master/examples/example_win32_directx11) application combines imgui_impl_win32.cpp + imgui_impl_dx11.cpp. There are 20+ examples in the [examples/](https://github.com/ocornut/imgui/blob/master/examples/) folder. See [EXAMPLES.MD](https://github.com/ocornut/imgui/blob/master/docs/EXAMPLES.md) for details.
 
 
 ### What are backends
@@ -36,7 +36,7 @@ Dear ImGui is highly portable and only requires a few things to run and render,
  - Optional: multi-viewports support.
  etc.
 
-This is essentially what each backends are doing + obligatory portability cruft.
+This is essentially what each backends are doing + obligatory portability cruft. Using default backends ensure you can get all those features including the ones that would be harder to implement on your side (e.g. multi-viewports support).
 
 It is important to understand the difference between the core Dear ImGui library (files in the root folder)
 and backends which we are describing here (backends/ folder).
@@ -46,6 +46,11 @@ and backends which we are describing here (backends/ folder).
   e.g. you can get creative and use software rendering or render remotely on a different machine.
 
 
+### Integrating a backend
+
+See "Getting Started" section of [EXAMPLES.MD](https://github.com/ocornut/imgui/blob/master/docs/EXAMPLES.md) for more details.
+
+
 ### List of backends
 
 In the [backends/](https://github.com/ocornut/imgui/blob/master/backends) folder: