I have problem during drag&drop of graphics object in QGLWidget. The issue is that QMouseEvent of QWidget::mouseMoveEvent is incorrect when:

1) I press the object by left mouse key without move and release,
2) switch to another window by alt+tab,
3) release left mouse key and move,
4) switch back to my application by alt+tab,
5) mouse move (no mouse key is pressed)

This sequence of actions causes that QWidget::mouseMoveEvent slot is called and QMouseEvent::buttons() contains Qt::LeftButton, which is incorrect! In buttons() should be Qt::NoButton, or am I wrong?

Thanks very much for reply