do not push new EventDelete if there was no deletion

src/mainwindow.cpp

@@ -2163,10 +2163,12 @@ void MainWindow::on_toolButton_deleteObject_clicked() {
                     logWarn(QString("Cannot delete event of type '%1'").arg(item->event->get("event_type")));
                 }
             }
+            if (numDeleted) {
                 editor->map->editHistory.push(new EventDelete(editor, editor->map, selectedEvents, nextSelectedEvent ? nextSelectedEvent->event : nullptr));
             }
         }
     }
+}
 
 void MainWindow::on_toolButton_Open_Scripts_clicked()
 {