Backends: OSX, Metal: Amend d111133, tidying up, remove unused, misc tweaks. . (#4821, #2778)

backends/imgui_impl_dx10.cpp

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_dx10.h

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D10ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_dx11.cpp

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_dx11.h

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'ID3D11ShaderResourceView*' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_dx12.cpp

@@ -3,9 +3,9 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 //      FIXME: The transition from removing a viewport and moving the window in an existing hosted viewport tends to flicker.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // Important: to compile on 32-bit systems, this backend requires code to be compiled with '#define ImTextureID ImU64'.
 // This is because we need ImTextureID to carry a 64-bit value and by default ImTextureID is defined as void*.

backends/imgui_impl_dx12.h

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'D3D12_GPU_DESCRIPTOR_HANDLE' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // Important: to compile on 32-bit systems, this backend requires code to be compiled with '#define ImTextureID ImU64'.
 // See imgui_impl_dx12.cpp file for details.

backends/imgui_impl_dx9.cpp

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_dx9.h

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'LPDIRECT3DTEXTURE9' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_metal.h

@@ -3,9 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
-// Missing features:
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [ ] Renderer: Multi-viewport / platform windows.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_metal.mm

@@ -3,8 +3,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'MTLTexture' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
-//  [X] Renderer: Multi-viewport / platform windows.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.
@@ -13,7 +13,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-05-03: Misc: Implemented support for viewports / platform windows.
+//  2022-XX-XX: Metal: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2022-04-27: Misc: Store backend data in a per-context struct, allowing to use this backend with multiple contexts.
 //  2022-01-03: Metal: Ignore ImDrawCmd where ElemCount == 0 (very rare but can technically be manufactured by user code).
 //  2021-12-30: Metal: Added Metal C++ support. Enable with '#define IMGUI_IMPL_METAL_CPP' in your imconfig.h file.

backends/imgui_impl_opengl2.cpp

@@ -3,7 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_opengl2.h

@@ -3,7 +3,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_opengl3.cpp

@@ -5,8 +5,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_opengl3.h

@@ -5,8 +5,8 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'GLuint' OpenGL texture identifier as void*/ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Multi-viewport support. Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
+//  [X] Renderer: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
-//  [x] Renderer: Desktop GL only: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [x] Renderer: Large meshes support (64k+ vertices) with 16-bit indices (Desktop OpenGL only).
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_osx.mm

@@ -24,7 +24,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2022-05-03: Misc: Implemented support for viewports / platform windows.
+//  2022-XX-XX: Added support for multiple windows via the ImGuiPlatformIO interface.
 //  2022-05-03: Inputs: Removed ImGui_ImplOSX_HandleEvent() from backend API in favor of backend automatically handling event capture.
 //  2022-04-27: Misc: Store backend data in a per-context struct, allowing to use this backend with multiple contexts.
 //  2022-03-22: Inputs: Monitor NSKeyUp events to catch missing keyUp for key when user press Cmd + key
@@ -864,18 +864,6 @@ static void ImGui_ImplOSX_DestroyWindow(ImGuiViewport* viewport)
     viewport->PlatformUserData = viewport->PlatformHandle = viewport->PlatformHandleRaw = NULL;
 }
 
-static void ImGui_ImplOSX_ShowWindow(ImGuiViewport* viewport)
-{
-    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
-    IM_ASSERT(data->Window != nil);
-}
-
-static void ImGui_ImplOSX_UpdateWindow(ImGuiViewport* viewport)
-{
-    ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
-    IM_ASSERT(data->Window != 0);
-}
-
 static ImVec2 ImGui_ImplOSX_GetWindowPos(ImGuiViewport* viewport)
 {
     ImGuiViewportDataOSX* data = (ImGuiViewportDataOSX*)viewport->PlatformUserData;
@@ -974,27 +962,11 @@ static float ImGui_ImplOSX_GetWindowDpiScale(ImGuiViewport* viewport)
     return data->Window.backingScaleFactor;
 }
 
-// FIXME-DPI: Testing DPI related ideas
-static void ImGui_ImplOSX_OnChangedViewport(ImGuiViewport* viewport)
-{
-    (void)viewport;
-#if 0
-    ImGuiStyle default_style;
-    //default_style.WindowPadding = ImVec2(0, 0);
-    //default_style.WindowBorderSize = 0.0f;
-    //default_style.ItemSpacing.y = 3.0f;
-    //default_style.FramePadding = ImVec2(0, 0);
-    default_style.ScaleAllSizes(viewport->DpiScale);
-    ImGuiStyle& style = ImGui::GetStyle();
-    style = default_style;
-#endif
-}
-
 static void ImGui_ImplOSX_UpdateMonitors()
 {
-    ImGui::GetPlatformIO().Monitors.resize(static_cast<int>(NSScreen.screens.count));
+    ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
+    platform_io.Monitors.resize(0);
 
-    int i = 0;
     for (NSScreen* screen in NSScreen.screens)
     {
         NSRect frame = screen.frame;
@@ -1007,9 +979,7 @@ static void ImGui_ImplOSX_UpdateMonitors()
         imgui_monitor.WorkSize = ImVec2(visibleFrame.size.width, visibleFrame.size.height);
         imgui_monitor.DpiScale = screen.backingScaleFactor;
 
-        ImGuiPlatformIO& io = ImGui::GetPlatformIO();
+        platform_io.Monitors.push_back(imgui_monitor);
-        io.Monitors[i] = imgui_monitor;
-        i += 1;
     }
 }
 
@@ -1022,7 +992,6 @@ static void ImGui_ImplOSX_InitPlatformInterface()
     ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
     platform_io.Platform_CreateWindow = ImGui_ImplOSX_CreateWindow;
     platform_io.Platform_DestroyWindow = ImGui_ImplOSX_DestroyWindow;
-    platform_io.Platform_ShowWindow = ImGui_ImplOSX_ShowWindow;
     platform_io.Platform_SetWindowPos = ImGui_ImplOSX_SetWindowPos;
     platform_io.Platform_GetWindowPos = ImGui_ImplOSX_GetWindowPos;
     platform_io.Platform_SetWindowSize = ImGui_ImplOSX_SetWindowSize;
@@ -1032,9 +1001,7 @@ static void ImGui_ImplOSX_InitPlatformInterface()
     platform_io.Platform_GetWindowMinimized = ImGui_ImplOSX_GetWindowMinimized;
     platform_io.Platform_SetWindowTitle = ImGui_ImplOSX_SetWindowTitle;
     platform_io.Platform_SetWindowAlpha = ImGui_ImplOSX_SetWindowAlpha;
-    platform_io.Platform_UpdateWindow = ImGui_ImplOSX_UpdateWindow;
     platform_io.Platform_GetWindowDpiScale = ImGui_ImplOSX_GetWindowDpiScale; // FIXME-DPI
-    platform_io.Platform_OnChangedViewport = ImGui_ImplOSX_OnChangedViewport; // FIXME-DPI
 
     // Register main window handle (which is owned by the main application, not by us)
     ImGuiViewport* main_viewport = ImGui::GetMainViewport();

backends/imgui_impl_sdlrenderer.cpp

@@ -10,7 +10,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 // Missing features:
 //  [ ] Renderer: Multi-viewport support (multiple windows).
 

backends/imgui_impl_sdlrenderer.h

@@ -10,7 +10,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'SDL_Texture*' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 // Missing features:
 //  [ ] Renderer: Multi-viewport support (multiple windows).
 

backends/imgui_impl_vulkan.cpp

@@ -2,8 +2,8 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
-//  [x] Platform: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
+//  [x] Renderer: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
 //  [!] Renderer: User texture binding. Use 'VkDescriptorSet' as ImTextureID. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
 
 // Important: on 32-bit systems, user texture binding is only supported if your imconfig file has '#define ImTextureID ImU64'.

backends/imgui_impl_vulkan.h

@@ -2,8 +2,8 @@
 // This needs to be used along with a Platform Backend (e.g. GLFW, SDL, Win32, custom..)
 
 // Implemented features:
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
-//  [x] Platform: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
+//  [x] Renderer: Multi-viewport / platform windows. With issues (flickering when creating a new viewport).
 //  [!] Renderer: User texture binding. Use 'VkDescriptorSet' as ImTextureID. Read the FAQ about ImTextureID! See https://github.com/ocornut/imgui/pull/914 for discussions.
 
 // Important: on 32-bit systems, user texture binding is only supported if your imconfig file has '#define ImTextureID ImU64'.

backends/imgui_impl_wgpu.cpp

@@ -4,7 +4,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this.
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

backends/imgui_impl_wgpu.h

@@ -4,7 +4,7 @@
 
 // Implemented features:
 //  [X] Renderer: User texture binding. Use 'WGPUTextureView' as ImTextureID. Read the FAQ about ImTextureID!
-//  [X] Renderer: Support for large meshes (64k+ vertices) with 16-bit indices.
+//  [X] Renderer: Large meshes support (64k+ vertices) with 16-bit indices.
 
 // You can use unmodified imgui_impl_* files in your project. See examples/ folder for examples of using this. 
 // Prefer including the entire imgui/ repository into your project (either as a copy or as a submodule), and only build the backends you need.

docs/CHANGELOG.txt

@@ -175,7 +175,6 @@ Other Changes:
 - Backends: OSX: Monitor NSKeyUp events to catch missing keyUp for key when user press Cmd + key (#5128) [@thedmd]
 - Backends: OSX, Metal: Store backend data in a per-context struct, allowing to use these backends with
   multiple contexts. (#5203, #5221, #4141) [@noisewuwei]
-- Backends: OSX, Metal: Implemented support for viewports / platform windows. [@stuartcarnie]
 - Examples: Emscripten+WebGPU: Fix building for latest WebGPU specs. (#3632)
 - Examples: OSX+Metal, OSX+OpenGL: Removed now-unnecessary calls to ImGui_ImplOSX_HandleEvent(). (#4821)
 
@@ -183,10 +182,12 @@ Docking+Viewports Branch:
 
 - Docking: Fixed floating docked nodes not being clamped into viewport workrect to stay reachable
   when g.ConfigWindowsMoveFromTitleBarOnly is set and multi-viewports are disabled. (#5044)
-- Backends: SDL: Fixed dragging out main viewport broken on some SDL setups. (#5012) [@rokups]
 - Viewports: Fixed translating a host viewport from briefly altering the size of AlwaysAutoResize windows. (#5057)
 - Viewports: Fixed main viewport size not matching ImDrawData::DisplaySize for one frame during resize
   when multi-viewports are disabled. (#4900)
+- Backends: SDL: Fixed dragging out main viewport broken on some SDL setups. (#5012) [@rokups]
+- Backends: OSX: Added suppot for multi-viewports. [@stuartcarnie, @metarutaiga] (#4821, #2778)
+- Backends: Metal: Added suppot for multi-viewports. [@stuartcarnie, @metarutaiga] (#4821, #2778)
 
 
 -----------------------------------------------------------------------

examples/example_apple_opengl2/main.mm

@@ -44,11 +44,20 @@
     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
     //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
     io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;           // Enable Docking
+    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;         // Enable Multi-Viewport / Platform Windows
 
     // Setup Dear ImGui style
     ImGui::StyleColorsDark();
     //ImGui::StyleColorsClassic();
 
+    // When viewports are enabled we tweak WindowRounding/WindowBg so platform windows can look identical to regular ones.
+    ImGuiStyle& style = ImGui::GetStyle();
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        style.WindowRounding = 0.0f;
+        style.Colors[ImGuiCol_WindowBg].w = 1.0f;
+    }
+
     // Setup Platform/Renderer backends
     ImGui_ImplOSX_Init(self);
     ImGui_ImplOpenGL2_Init();
@@ -131,6 +140,13 @@
 
     ImGui_ImplOpenGL2_RenderDrawData(draw_data);
 
+    // Update and Render additional Platform Windows
+    if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+    {
+        ImGui::UpdatePlatformWindows();
+        ImGui::RenderPlatformWindowsDefault();
+    }
+
     // Present
     [[self openGLContext] flushBuffer];