Volume Mixer renders incorrectly in RTM

Hi,

in the RTM of Vista I'm getting a garbled up Volume Mixer i.e. the
one from right-click in icon tray and Open Volume Mixer. Disabled
Aero, no difference. Sometimes the sliders have a kind of black
background around them, sometimes especially with the vertical
scroll for "Applications" visible all application icons and the
sliders just draw completely jumbled, a mess. Anyone know if there's
some resolution/workaround to this by now?

- Jan