Fixed incorrect assert in FocusTopMostWindowUnderOne() preventing child+popup from being used. (#6915, #718)

imgui.cpp

@@ -7145,7 +7145,6 @@ void ImGui::FocusTopMostWindowUnderOne(ImGuiWindow* under_this_window, ImGuiWind
     {
         // We may later decide to test for different NoXXXInputs based on the active navigation input (mouse vs nav) but that may feel more confusing to the user.
         ImGuiWindow* window = g.WindowsFocusOrder[i];
-        IM_ASSERT(window == window->RootWindow);
         if (window == ignore_window || !window->WasActive)
             continue;
         if ((window->Flags & (ImGuiWindowFlags_NoMouseInputs | ImGuiWindowFlags_NoNavInputs)) != (ImGuiWindowFlags_NoMouseInputs | ImGuiWindowFlags_NoNavInputs))