How to appropriately use ctkPluginFrameworkLauncher::stop()

[haomehaode]

Dear CTK Developer,
I am facing a strange problem as I quit a GUI app. I believe it is related to multiple threads. Here is a snapshot of the main function where the ctkPluginFramework is initialized. To test if all plugin could be removed once the stop function is called, a line is added as follows,

QApplication app(argc, argv);

ctkPluginFrameworkLauncher::addSearchPath(QCoreApplication::applicationDirPath() + "/plugins");
bool success = ctkPluginFrameworkLauncher::start("org.commontk.eventadmin");
ctkPluginContext* context = ctkPluginFrameworkLauncher::getPluginContext();

QString path = QCoreApplication::applicationDirPath() + "/plugins";
QDirIterator itPlugin(path, QStringList() << "*.dll" << "*.so", QDir::Files);
while (itPlugin.hasNext()) {
	QString strPlugin = itPlugin.next();
	try {
		QSharedPointer<ctkPlugin> plugin = context->installPlugin(QUrl::fromLocalFile(strPlugin));
		plugin->start(ctkPlugin::START_TRANSIENT);
		qDebug() << "Plugin start ..." << strPlugin;
	}
	catch (const ctkPluginException& e) {
		qDebug() << "Failed to install plugin" << e.what();
		return -1;
	}
}

ctkServiceReference reference = context->getServiceReference<IMainWindow>();
if (reference) {
	IMainWindow* service = qobject_cast<IMainWindow*>(context->getService(reference));
	if (service != Q_NULLPTR) {
		service->init();
	}
}

ctkPluginFrameworkLauncher::stop();

Here is a snapshot of what occur, with this I believe it is a multiple thread issue. I would like to take some advice on how(or where) to use ctkPluginFrameworkLauncher::stop().

If I comment out the code

//ctkPluginFrameworkLauncher::stop();
Here is a snapshot of what occur

I hope you can give me some suggestions，Thanks