#include <QApplication>
#include <QPushButton>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

	auto* w = new QPushButton(nullptr);
	w->resize(QSize(200,200));
	w->setWindowFlag(Qt::Popup);

	QObject::connect(w, &QPushButton::clicked, [w](bool) {
		auto geo = w->saveGeometry();
		w->restoreGeometry(geo);
	});
	w->show();

    return app.exec();
}