Extra leave event when leaving window with mouse held

If you hold a mouse button down while moving the mouse out of the application window, the widget that got the mouse-down event will receive a Leave event when the mouse leaves the application window, and again when your release the mouse button. In Qt4, only the last event triggered a Leave event.

Note that the leave event is correctly suppressed when leaving the widget when holding the mouse button down. The extra leave event is only triggered when leaving the application window.

It seems to be a fault in how autograbbing the mouse works, and that QApplication::sendMouseEvent does not, and can check if a widget has been auto-grabbed.