diff --git a/imgui.cpp b/imgui.cpp
index 54fe7dc64..3d98a6055 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -10986,7 +10986,7 @@ static void ImGui::UpdateSelectWindowViewport(ImGuiWindow* window)
             ImVec2 mouse_ref = (flags & ImGuiWindowFlags_Tooltip) ? g.IO.MousePos : g.BeginPopupStack.back().OpenMousePos;
             bool use_mouse_ref = (g.NavDisableHighlight || !g.NavDisableMouseHover || !g.NavWindow);
             bool mouse_valid = IsMousePosValid(&mouse_ref);
-            if ((window->Appearing || (flags & ImGuiWindowFlags_Tooltip)) && (!use_mouse_ref || mouse_valid))
+            if ((window->Appearing || (flags & (ImGuiWindowFlags_Tooltip | ImGuiWindowFlags_ChildMenu))) && (!use_mouse_ref || mouse_valid))
                 window->ViewportAllowPlatformMonitorExtend = FindPlatformMonitorForPos((use_mouse_ref && mouse_valid) ? mouse_ref : NavCalcPreferredRefPos());
             else
                 window->ViewportAllowPlatformMonitorExtend = window->Viewport->PlatformMonitor;