mac os fix

src/core/UBSceneCache.cpp

@@ -127,8 +127,11 @@ UBGraphicsScene* UBSceneCache::value(UBDocumentProxy* proxy, int pageIndex)
 void UBSceneCache::removeScene(UBDocumentProxy* proxy, int pageIndex)
 {
     UBGraphicsScene* scene = value(proxy, pageIndex);
-
+#ifdef Q_WS_MAC 
+    if (scene && scene->views().size() == 0)
+#else
     if (scene && !scene->isActive())
+#endif
     {
         UBSceneCacheID key(proxy, pageIndex);
         int count = QHash<UBSceneCacheID, UBGraphicsScene*>::remove(key);