MouseArea: Drag aborted after leaving window

When starting a drag from a MouseArea and then leaving the QtQuick window with the mouse cursor, the drag is not resumed after entering the window again. This works on other platforms, but not Linux.

To reproduce, use the attached example. Drag the blue rectangle out of the window, then (still holding the mouse button down) re-enter the window with the mouse cursor. Expectation: The drag continues (i.e. blue rectangle is moved) as soon as the mouse enters the window again. Actual outcome: The drag is aborted as soon as the mouse cursor leaves the window.

Tested with:
qtbase: v5.0.0-299-g3d9a400
qtjsbackend: v5.0.0-2-gce0de18
qtdeclarative: v5.0.0-35-gd89f1db