diff --git a/src/gtk/dialog.cpp b/src/gtk/dialog.cpp
index d1d13da9b3..e948cddd10 100644
--- a/src/gtk/dialog.cpp
+++ b/src/gtk/dialog.cpp
@@ -198,7 +198,7 @@ int wxDialog::ShowModal()
     if ( !GetParent() && !(GetWindowStyleFlag() & wxDIALOG_NO_PARENT) )
     {
         wxWindow *parent = wxTheApp->GetTopWindow();
-        if ( parent && parent != this )
+        if ( parent && parent != this && parent->IsBeingDeleted() )
         {
             m_parent = parent;
             gtk_window_set_transient_for( GTK_WINDOW(m_widget), GTK_WINDOW(parent->m_widget) );
diff --git a/src/gtk1/dialog.cpp b/src/gtk1/dialog.cpp
index d1d13da9b3..e948cddd10 100644
--- a/src/gtk1/dialog.cpp
+++ b/src/gtk1/dialog.cpp
@@ -198,7 +198,7 @@ int wxDialog::ShowModal()
     if ( !GetParent() && !(GetWindowStyleFlag() & wxDIALOG_NO_PARENT) )
     {
         wxWindow *parent = wxTheApp->GetTopWindow();
-        if ( parent && parent != this )
+        if ( parent && parent != this && parent->IsBeingDeleted() )
         {
             m_parent = parent;
             gtk_window_set_transient_for( GTK_WINDOW(m_widget), GTK_WINDOW(parent->m_widget) );
diff --git a/src/msw/toplevel.cpp b/src/msw/toplevel.cpp
index 0720766612..8874a8d156 100644
--- a/src/msw/toplevel.cpp
+++ b/src/msw/toplevel.cpp
@@ -192,6 +192,12 @@ bool wxTopLevelWindowMSW::CreateDialog(const wxChar *dlgTemplate,
     if ( !parent && !(GetWindowStyleFlag() & wxDIALOG_NO_PARENT) )
     {
         parent = wxTheApp->GetTopWindow();
+
+        // but don't use the window which is about to be destroyed as parent
+        if ( parent->IsBeingDeleted() )
+        {
+            parent = NULL;
+        }
     }
 
     m_hWnd = (WXHWND)::CreateDialog(wxGetInstance(),