(svn r12942) -Fix [FS#1979]: closing some windows caused recursion in the Window deletion causing the reading invalid/freed data which could cause crashes.

src/window.cpp

@@ -416,35 +416,37 @@ void DeleteWindow(Window *w)
 {
 	if (w == NULL) return;
 
-	/* Delete any children a window might have in a head-recursive manner */
-	Window *v = FindChildWindow(w);
-	if (v != NULL) DeleteWindow(v);
-
 	if (_thd.place_mode != VHM_NONE &&
 			_thd.window_class == w->window_class &&
 			_thd.window_number == w->window_number) {
 		ResetObjectToPlace();
 	}
 
-	CallWindowEventNP(w, WE_DESTROY);
-	if (w->viewport != NULL) DeleteWindowViewport(w);
-
-	SetWindowDirty(w);
-	free(w->widget);
-	w->widget = NULL;
-	w->widget_count = 0;
-	w->parent = NULL;
-
 	/* Prevent Mouseover() from resetting mouse-over coordinates on a non-existing window */
 	if (_mouseover_last_w == w) _mouseover_last_w = NULL;
 
 	/* Find the window in the z-array, and effectively remove it
-	 * by moving all windows after it one to the left */
+	 * by moving all windows after it one to the left. This must be
+	 * done before removing the child so we cannot cause recursion
+	 * between the deletion of the parent and the child. */
 	Window **wz = FindWindowZPosition(w);
 	if (wz == NULL) return;
 	memmove(wz, wz + 1, (byte*)_last_z_window - (byte*)wz);
 	_last_z_window--;
 
+	/* Delete any children a window might have in a head-recursive manner */
+	Window *v = FindChildWindow(w);
+	if (v != NULL) DeleteWindow(v);
+
+	CallWindowEventNP(w, WE_DESTROY);
+	if (w->viewport != NULL) DeleteWindowViewport(w);
+
+	SetWindowDirty(w);
+	free(w->widget);
+	w->widget = NULL;
+	w->widget_count = 0;
+	w->parent = NULL;
+
 	delete w;
 }