diff --git a/dlls/winex11.drv/window.c b/dlls/winex11.drv/window.c
index 595c54a7c0a..a16b8354245 100644
--- a/dlls/winex11.drv/window.c
+++ b/dlls/winex11.drv/window.c
@@ -1209,12 +1209,16 @@ static void X11DRV_window_to_X_rect( struct x11drv_win_data *data, RECT *rect,
  */
 void X11DRV_X_to_window_rect( struct x11drv_win_data *data, RECT *rect, int x, int y, int cx, int cy )
 {
-    x += data->window_rect.left - data->whole_rect.left;
-    y += data->window_rect.top - data->whole_rect.top;
-    cx += (data->window_rect.right - data->window_rect.left) -
-          (data->whole_rect.right - data->whole_rect.left);
-    cy += (data->window_rect.bottom - data->window_rect.top) -
-          (data->whole_rect.bottom - data->whole_rect.top);
+    RECT rc;
+
+    get_decoration_rect( data, &rc, &data->window_rect, &data->client_rect );
+
+    x += min( data->window_rect.left - data->whole_rect.left, rc.left );
+    y += min( data->window_rect.top - data->whole_rect.top, rc.top );
+    cx += max( (data->window_rect.right - data->window_rect.left) -
+               (data->whole_rect.right - data->whole_rect.left), rc.right - rc.left );
+    cy += max( (data->window_rect.bottom - data->window_rect.top) -
+               (data->whole_rect.bottom - data->whole_rect.top), rc.bottom - rc.top );
     SetRect( rect, x, y, x + cx, y + cy );
 }