fixed an issue where erase a stroke then clear the scene before changing page would cause a crash

src/board/UBBoardController.cpp

@@ -1632,11 +1632,11 @@ void UBBoardController::moveSceneToIndex(int source, int target)
     }
 }
 
-void UBBoardController::findUniquesItems(const QUndoCommand *parent, QSet<QGraphicsItem*> &itms)
+void UBBoardController::findUniquesItems(const QUndoCommand *parent, QSet<QGraphicsItem*> &items)
 {
     if (parent->childCount()) {
         for (int i = 0; i < parent->childCount(); i++) {
-            findUniquesItems(parent->child(i), itms);
+            findUniquesItems(parent->child(i), items);
         }
     }
 
@@ -1657,16 +1657,26 @@ void UBBoardController::findUniquesItems(const QUndoCommand *parent, QSet<QGraph
     while (itAdded.hasNext())
     {
         QGraphicsItem* item = itAdded.next();
-        if( !itms.contains(item) && !(item->parentItem() && UBGraphicsGroupContainerItem::Type == item->parentItem()->type()))
-            itms.insert(item);
+        if (!items.contains(item) &&
+            !(item->parentItem() && UBGraphicsGroupContainerItem::Type == item->parentItem()->type()) &&
+            !items.contains(item->parentItem())
+            )
+        {
+            items.insert(item);
+        }
     }
 
     QSetIterator<QGraphicsItem*> itRemoved(cmd->GetRemovedList());
     while (itRemoved.hasNext())
     {
         QGraphicsItem* item = itRemoved.next();
-        if( !itms.contains(item) && !(item->parentItem() && UBGraphicsGroupContainerItem::Type == item->parentItem()->type()))
-            itms.insert(item);
+        if (!items.contains(item) &&
+            !(item->parentItem() && UBGraphicsGroupContainerItem::Type == item->parentItem()->type()) &&
+            !items.contains(item->parentItem())
+            )
+        {
+            items.insert(item);
+        }
     }
 }
 

src/board/UBBoardController.h

@@ -177,7 +177,7 @@ class UBBoardController : public UBDocumentContainer
         void notifyPageChanged();
         void displayMetaData(QMap<QString, QString> metadatas);
 
-        void findUniquesItems(const QUndoCommand *parent, QSet<QGraphicsItem *> &itms);
+        void findUniquesItems(const QUndoCommand *parent, QSet<QGraphicsItem *> &items);
         void ClearUndoStack();
 
         void setActiveDocumentScene(UBDocumentProxy* pDocumentProxy, int pSceneIndex = 0, bool forceReload = false, bool onImport = false);