(svn r7635) -Fix (r7618, r7621): Guard against recursive deletion. It is possible that when a

parent window is deleted it deletes its child (always) and in turn, through some
 code the child initiates the deletion of the parent which, if not guarded
 against, deletes the child and so on...

misc_gui.c

@@ -1226,7 +1226,10 @@ static void QueryWndProc(Window *w, WindowEvent *e)
 			break;
 
 		case WE_DESTROY: /* Call callback function (if any) on window close if not yet called */
-			if (!q->calledback && q->proc != NULL) q->proc(w->parent, false);
+			if (!q->calledback && q->proc != NULL) {
+				q->calledback = true;
+				q->proc(w->parent, false);
+			}
 			break;
 	}
 }

window.c

@@ -308,10 +308,13 @@ Window **FindWindowZPosition(const Window *w)
 {
 	Window **wz;
 
-	for (wz = _z_windows;; wz++) {
-		assert(wz < _last_z_window);
+	for (wz = _z_windows; wz != _last_z_window; wz++) {
 		if (*wz == w) return wz;
 	}
+
+	DEBUG(misc, 3, "Window (class %d, number %d) is not open, probably removed by recursive calls",
+		w->window_class, w->window_number);
+	return NULL;
 }
 
 void DeleteWindow(Window *w)
@@ -342,6 +345,7 @@ void DeleteWindow(Window *w)
 	/* Find the window in the z-array, and effectively remove it
 	 * by moving all windows after it one to the left */
 	wz = FindWindowZPosition(w);
+	if (wz == NULL) return;
 	memmove(wz, wz + 1, (byte*)_last_z_window - (byte*)wz);
 	_last_z_window--;
 }