EndMainMenuBar doesn't attempt to restore focus when there's an active id. (ocornut#8355)

I don't have a specific issue in mind but it seems sane to add that test.

Author: ocornut

imgui_widgets.cpp

@@ -8769,7 +8769,7 @@ void ImGui::EndMainMenuBar()
     // When the user has left the menu layer (typically: closed menus through activation of an item), we restore focus to the previous window
     // FIXME: With this strategy we won't be able to restore a NULL focus.
     ImGuiContext& g = *GImGui;
-    if (g.CurrentWindow == g.NavWindow && g.NavLayer == ImGuiNavLayer_Main && !g.NavAnyRequest)
+    if (g.CurrentWindow == g.NavWindow && g.NavLayer == ImGuiNavLayer_Main && !g.NavAnyRequest && g.ActiveId == 0)
         FocusTopMostWindowUnderOne(g.NavWindow, NULL, NULL, ImGuiFocusRequestFlags_UnlessBelowModal | ImGuiFocusRequestFlags_RestoreFocusedChild);
 
     End();