diff --git a/src/gtk/mdi.cpp b/src/gtk/mdi.cpp
index 5726755278..69a709e439 100644
--- a/src/gtk/mdi.cpp
+++ b/src/gtk/mdi.cpp
@@ -250,7 +250,7 @@ static void SetInvokingWindow( wxMenu *menu, wxWindow *win )
   while (node)
   {
     wxMenuItem *menuitem = (wxMenuItem*)node->Data();
-    if (menuitem->m_isSubMenu) SetInvokingWindow( menuitem->m_subMenu, win );
+    if (menuitem->GetSubMenu()) SetInvokingWindow( menuitem->GetSubMenu(), win );
     node = node->Next();
   };
 };
diff --git a/src/gtk1/mdi.cpp b/src/gtk1/mdi.cpp
index 5726755278..69a709e439 100644
--- a/src/gtk1/mdi.cpp
+++ b/src/gtk1/mdi.cpp
@@ -250,7 +250,7 @@ static void SetInvokingWindow( wxMenu *menu, wxWindow *win )
   while (node)
   {
     wxMenuItem *menuitem = (wxMenuItem*)node->Data();
-    if (menuitem->m_isSubMenu) SetInvokingWindow( menuitem->m_subMenu, win );
+    if (menuitem->GetSubMenu()) SetInvokingWindow( menuitem->GetSubMenu(), win );
     node = node->Next();
   };
 };