Ensure the validity of hOldFocus before calling WIN_GetTopParent.
diff --git a/windows/winpos.c b/windows/winpos.c
index 121f650..e2f56e4 100644
--- a/windows/winpos.c
+++ b/windows/winpos.c
@@ -1855,7 +1855,7 @@
{
HWND hOldFocus = PERQDATA_GetFocusWnd( pNewActiveQueue->pQData );
- if ( WIN_GetTopParent( hOldFocus ) != hwndActive )
+ if ( hOldFocus && WIN_GetTopParent( hOldFocus ) != hwndActive )
FOCUS_SwitchFocus( pNewActiveQueue, hOldFocus,
(wndPtr && (wndPtr->dwStyle & WS_MINIMIZE))?
0 : hwndActive );