Docking: Fixed a bug undocking windows docked into a non-visible or _KeepAliveOnly dockspace. (#4757)

docs/CHANGELOG.txt

@@ -145,6 +145,8 @@ Other Changes:
 Docking+Viewports Branch:
 
 - Docking: Revert removal of io.ConfigDockingWithShift config option (removed in 1.83). (#4643)
+- Docking: Fixed a bug undocking windows docked into a non-visible or _KeepAliveOnly dockspace
+  when unrelated windows submitted before the dockspace have dynamic visibility. (#4757)
 - Viewports: Made it possible to explicitly assign ImGuiWindowClass::ParentViewportId to 0 in order
   to ensure a window is not parented. Previously this would use the global default (which might be 0,
   but not always as it would depend on io.ConfigViewportsNoDefaultParent). (#3152, #2871)

imgui.cpp

@@ -16157,7 +16157,7 @@ void ImGui::BeginDocked(ImGuiWindow* window, bool* p_open)
     node->State = ImGuiDockNodeState_HostWindowVisible;
 
     // Undock if we are submitted earlier than the host window
-    if (window->BeginOrderWithinContext < node->HostWindow->BeginOrderWithinContext)
+    if (!(node->MergedFlags & ImGuiDockNodeFlags_KeepAliveOnly) && window->BeginOrderWithinContext < node->HostWindow->BeginOrderWithinContext)
     {
         DockContextProcessUndockWindow(ctx, window);
         return;