https://bugs.freedesktop.org/show_bug.cgi?id=36934
--- Comment #14 from auxsvr@gmail.com 2011-10-22 06:11:24 PDT --- I spoke too soon: minor, transient corruption still occurs. For example, for some seconds the glyph "u" would disappear from the panel and some widgets became corrupted. After a while, everything returned to normal. Maybe the virtualbox kernel modules were causing further corruption that started elsewhere?