When using qtdotnetstyle as the base style and then applying a style-sheet that customizes the look of QTabBars then background colors (supplied via the qtdotnetstyle style) for menu-bars, tool-bars splitters, and tab-bars (and perhaps others) are drawn incorrectly.

The stylesheet documentation states that stylesheets are not supported for custom QStyle subclasses, but since qtdotnetstyle is provided by Trolltech, then maybe something can be done to fix this problem in the qtdotnetstyle.