weired console message with simple application

qt.pointer.dispatch: skipping QEventPoint(id=1 ts=0 pos=0,0 scn=282.967,161.171 gbl=282.967,161.171 Released ellipse=(1x1 ∡ 0) vel=0,0 press=-282.967,-161.171 last=-282.967,-161.171 Δ 282.967,161.171) : no target window 

#include <QtWidgets>

class myWidget : public QWidget
{
public:
    myWidget(QWidget *parent=nullptr) :
        QWidget::QWidget(parent) {}
    virtual ~myWidget() {}
private:
    void mouseMoveEvent(QMouseEvent *) {}
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QMainWindow w;
    auto m = new QMdiArea;
    myWidget *widget = new myWidget;
    widget->setMinimumSize(QSize(400,300));
    m->addSubWindow(widget);
    w.setCentralWidget(m);
    w.show();
    app.exec();
}