mainwindow: don't delete lrc instance on close event

Change-Id: Ib9ae1b6668df728a9e74331b99a3394418fe354e

mainwindow.cpp

@@ -290,9 +290,8 @@ MainWindow::closeEvent(QCloseEvent* event)
         settings.setValue(SettingsKey::geometry, saveGeometry());
         settings.setValue(SettingsKey::windowState, saveState());
     }
-    this->disconnect(screenChangedConnection_);
     this->disconnect(activeChangedConnection_);
-    LRCInstance::reset();
+    this->disconnect(screenChangedConnection_);
     QMainWindow::closeEvent(event);
 }