Hi Mike,
This is one of the long standing, style sheet related Qt bugs that we have been suffering for years. Since nobody seems interested in fixing this type of bugs in Qt 4, I have no hope to see it fixed.
I plan to make the transition to Qt 5, now that it looks reasonably mature (fingers crossed, hands and feet), in 2015. Qt 5 should be a major improvement in many areas, although widget-based desktop applications are not a priority nowadays, and the people that lead Qt development are no exception (development is mainly focused on mobile devices, which is where the money is)...