Windows not updated with backingstore enabled

[Martin Vollrathson]

Hello.
I have an annoying problem with backingstore. Windows are often not
updated when I switch workspace or drag other windows over them. With
"not updated" I mean that the content in affected areas is replaced with
the solid background color of that window. This problem occurs only with
xorg ati-drivers >= 6.5.8.0 on my Radeon 9200 SE (RV280). If I turn off
backingstore everything is redrawn as expected but I would prefer to
have backingstore turned on. Any clues?

/Martin