Viewports: Fixed a CTRL+TAB crash with viewports enabled (#4023, #787)…

… (amend 1dc3af3, 23ef6c1, 657073a)

+ Expose FindHoveredViewportFromPlatformWindowStack() in imgui_internal.h

docs/CHANGELOG.txt

@@ -108,6 +108,11 @@ Other changes:
 - Backends: Metal: Added Apple Metal C++ API support. (#4824, #4746) [@luigifcruz]
   Enable with '#define IMGUI_IMPL_METAL_CPP' in your imconfig.h file.
 
+Docking+Viewports Branch:
+
+- Viewports: Fixed a CTRL+TAB crash with viewports enabled when the window list needs to appears in
+  its own viewport (regression from 1.86). (#4023, #787)
+
 
 -----------------------------------------------------------------------
  VERSION 1.86 (Released 2021-12-22)

imgui.cpp

@@ -4700,7 +4700,7 @@ static void ImGui::RenderDimmedBackgrounds()
     {
         // Draw dimming behind CTRL+Tab target window and behind CTRL+Tab UI window
         RenderDimmedBackgroundBehindWindow(g.NavWindowingTargetAnim, GetColorU32(ImGuiCol_NavWindowingDimBg, g.DimBgRatio));
-        if (g.NavWindowingListWindow != NULL && g.NavWindowingListWindow->Viewport != g.NavWindowingTargetAnim->Viewport)
+        if (g.NavWindowingListWindow != NULL && g.NavWindowingListWindow->Viewport && g.NavWindowingListWindow->Viewport != g.NavWindowingTargetAnim->Viewport)
             RenderDimmedBackgroundBehindWindow(g.NavWindowingListWindow, GetColorU32(ImGuiCol_NavWindowingDimBg, g.DimBgRatio));
         viewports_already_dimmed[0] = g.NavWindowingTargetAnim->Viewport;
         viewports_already_dimmed[1] = g.NavWindowingListWindow ? g.NavWindowingListWindow->Viewport : NULL;
@@ -12143,7 +12143,7 @@ void ImGui::ScaleWindowsInViewport(ImGuiViewportP* viewport, float scale)
 // If the backend doesn't set MouseLastHoveredViewport or doesn't honor ImGuiViewportFlags_NoInputs, we do a search ourselves.
 // A) It won't take account of the possibility that non-imgui windows may be in-between our dragged window and our target window.
 // B) It requires Platform_GetWindowFocus to be implemented by backend.
-static ImGuiViewportP* FindHoveredViewportFromPlatformWindowStack(const ImVec2 mouse_platform_pos)
+ImGuiViewportP* ImGui::FindHoveredViewportFromPlatformWindowStack(const ImVec2& mouse_platform_pos)
 {
     ImGuiContext& g = *GImGui;
     ImGuiViewportP* best_candidate = NULL;

imgui_internal.h

@@ -2694,7 +2694,8 @@ namespace ImGui
     IMGUI_API void          ScaleWindowsInViewport(ImGuiViewportP* viewport, float scale);
     IMGUI_API void          DestroyPlatformWindow(ImGuiViewportP* viewport);
     IMGUI_API void          SetCurrentViewport(ImGuiWindow* window, ImGuiViewportP* viewport);
-    IMGUI_API const ImGuiPlatformMonitor* GetViewportPlatformMonitor(ImGuiViewport* viewport);
+    IMGUI_API const ImGuiPlatformMonitor*   GetViewportPlatformMonitor(ImGuiViewport* viewport);
+    IMGUI_API ImGuiViewportP*               FindHoveredViewportFromPlatformWindowStack(const ImVec2& mouse_platform_pos);
 
     // Settings
     IMGUI_API void                  MarkIniSettingsDirty();