I can confirm the bug (on karmic), only that it is unlikely that it should be assigned to emacs.
I have reproduced the problem with emacs-snapshot-gtk (karmic), emacs23-gtk (compiled from debian source packages) and the FSF sanctioned vanilla tarballs of emacs23.
In all those cases the X toolkit version works fine.
I can confirm the bug (on karmic), only that it is unlikely that it should be assigned to emacs.
I have reproduced the problem with emacs-snapshot-gtk (karmic), emacs23-gtk (compiled from debian source packages) and the FSF sanctioned vanilla tarballs of emacs23.
In all those cases the X toolkit version works fine.