improvements on multiple selected documents handling

src/document/UBDocumentContainer.cpp

@@ -137,8 +137,15 @@ void UBDocumentContainer::deleteThumbPage(int index)
 
 void UBDocumentContainer::updateThumbPage(int index)
 {
-    mDocumentThumbs[index] = UBThumbnailAdaptor::get(mCurrentDocument, index);
-    emit documentPageUpdated(index);
+    if (mDocumentThumbs.size() > index)
+    {
+        mDocumentThumbs[index] = UBThumbnailAdaptor::get(mCurrentDocument, index);
+        emit documentPageUpdated(index);
+    }
+    else
+    {
+        qDebug() << "error [updateThumbPage] : index > mDocumentThumbs' size.";
+    }
 }
 
 void UBDocumentContainer::insertThumbPage(int index)

src/document/UBDocumentController.h

@@ -434,6 +434,8 @@ class UBDocumentController : public UBDocumentContainer
 
         void createNewDocumentGroup();
         void deleteSelectedItem();
+        void deleteSingleItem(QModelIndex index, UBDocumentTreeModel *docModel);
+        void deleteMultipleItems(QModelIndexList indexes, UBDocumentTreeModel *docModel);
         void emptyFolder(const QModelIndex &index, DeletionType pDeletionType = MoveToTrash);
         void deleteIndexAndAssociatedData(const QModelIndex &pIndex);
         void renameSelectedItem();