Problem with fonts on Linux with compositing activated

Hi,

I've switched to KDE4 and played with composite rendering.  With last squeak dev images some fonts are not rendered: it seems to be interpreted as a transparent region by the composite manager (see screenshot). I've tested this on my two debian boxes.

This problem is not present in sq3.9.1-7075dev08.07.1 image, so I suppose it's due to NiceFont integration ? 

Regards,
--
Laurent Laffont