Docking+Viewport: Fixed PlatformRequestClose (e.g. ALT-F4) being redrected to the first window of the docking node instead of the selected one.

imgui.cpp

@@ -5421,11 +5421,14 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
         // Close from platform window
         if (p_open != NULL && window->Viewport->PlatformRequestClose && window->Viewport != GetMainViewport())
+        {
+            if (!window->DockIsActive || window->DockTabIsVisible)
             {
                 window->Viewport->PlatformRequestClose = false;
                 g.NavWindowingToggleLayer = false; // Assume user mapped PlatformRequestClose on ALT-F4 so we disable ALT for menu toggle. False positive not an issue.
                 *p_open = false;
             }
+        }
 
         // Title bar
         if (!(flags & ImGuiWindowFlags_NoTitleBar) && !window->DockIsActive)