The bug is gone in Ubuntu 10.04 alpha 2 with these packages :
xserver-xorg-core 2:1.7.3.902-1ubuntu5 gnome-settings-daemon 2.28.1-1ubuntu2
Therefore it seems to be fixed.
The bug is gone in Ubuntu 10.04 alpha 2 with these packages :
xserver-xorg-core 2:1.7.3. 902-1ubuntu5 daemon 2.28.1-1ubuntu2
gnome-settings-
Therefore it seems to be fixed.