insertthumbpage in board mode only if the same document is selected in both modes

src/core/UBDocumentManager.cpp

@@ -286,6 +286,7 @@ int UBDocumentManager::addFilesToDocument(UBDocumentProxy* document, QStringList
                         UBGraphicsScene* scene = UBPersistenceManager::persistenceManager()->createDocumentSceneAt(document, pageIndex);
                         importAdaptor->placeImportedItemToScene(scene, page);
                         UBPersistenceManager::persistenceManager()->persistDocumentScene(document, scene, pageIndex);
+                        if (UBApplication::documentController->selectedDocument() == UBApplication::boardController->selectedDocument())
                             UBApplication::boardController->insertThumbPage(pageIndex);
                     }