MouseArea as a child of smoot and clip item removes smoothness.

See the attached QML file for reproducing the problem.
See the attached image for a snapshot illustrating the problem.

Both rectangles have the smooth and clip properties set to true. The right rectangle has a mouse area on top of it. The left rectangle is without a mouse area.
It seem that the mouse area is causing this problem.

Note, setting clip to false removes the problem.

I also reproduced this with Qt 4.7 snapshot from 14.8.2010.