call treeViewSelectionChanged just once

src/document/UBDocumentController.cpp

@@ -1548,7 +1548,6 @@ void UBDocumentTreeView::dropEvent(QDropEvent *event)
                 const QPixmap *pix = new QPixmap(thumbTmp);
                 UBDocumentController *ctrl = UBApplication::documentController;
                 ctrl->addPixmapAt(pix, toIndex);
-                ctrl->TreeViewSelectionChanged(ctrl->firstSelectedTreeIndex(), QModelIndex());
             }
 
             QApplication::restoreOverrideCursor();
@@ -1557,6 +1556,8 @@ void UBDocumentTreeView::dropEvent(QDropEvent *event)
             docModel->setHighLighted(QModelIndex());
         }
 
+        UBApplication::documentController->TreeViewSelectionChanged(UBApplication::documentController->firstSelectedTreeIndex(), QModelIndex());
+
     }
     else
     {