QWidgets never receive swipe gestures

#include <QApplication>
#include <QGestureEvent>
#include <QMainWindow>

class MainWindow: public QMainWindow
{
protected:
    bool event(QEvent* e) override
    {
        if (e->type() == QEvent::Gesture) {
            auto* gestEv = static_cast<QGestureEvent*>(e);
            if (gestEv->gesture(Qt::SwipeGesture) != nullptr) {
                abort();
            }
        }
        return false;
    }
};

int main(int argc, char* argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.grabGesture(Qt::SwipeGesture);
    w.show();
    return a.exec();
}