As this thread in xfce's bugzilla suggests, the bug should be fixed in the latest version of xfce4-xkb-plugin, which is 0.5.4.1 (as opposed to 0.5.3.3 in both Ubuntu 11.04 and Debian Squeeze):
https://bugzilla.xfce.org/show_bug.cgi?id=6321
As this thread in xfce's bugzilla suggests, the bug should be fixed in the latest version of xfce4-xkb-plugin, which is 0.5.4.1 (as opposed to 0.5.3.3 in both Ubuntu 11.04 and Debian Squeeze):
https:/ /bugzilla. xfce.org/ show_bug. cgi?id= 6321