stacking_list contains ObWindows that may or may not be ObClients

openbox/action.c

@@ -1095,6 +1095,7 @@ void action_raiselower(union ActionData *data)
     gboolean raise = FALSE;
 
     for (it = stacking_list; it; it = g_list_next(it)) {
+        if (WINDOW_IS_CLIENT(it->data)) {
             ObClient *cit = it->data;
 
             if (cit == c) break;
@@ -1109,6 +1110,7 @@ void action_raiselower(union ActionData *data)
                 }
             }
         }
+    }
 
     if (raise)
         action_raise(data);