crash on null commit using bzr qcommit --ui-mode in branch of shared repo

Using bzr-explorer (that's how I found this issue, may not be the only way):
Initialized a shared repo (selected "Feature Branches" in init dialog) called 'test-project'
Output pane (of init) shows that the shared repo has been created *and* a branch called trunk has been created inside the repo.

Open location of shared repo, double click on branch 'trunk'.
So now we are staring at an up-to-date branch 'trunk at revision 0.
So invoke commit anyway and when prompted say 'yes, commit even though no changes' ==> crash dump attached.

Just for sanity, go to the command line and issue

$ bzr commit --unchanged -m "null commit"
Committing to: /home/maritza/Projects/test-project/trunk/
Committed revision 1.

No problem on the command line. Per Alexander, this may (?) be related to Bug #299879 (https://bugs.launchpad.net/bzr/+bug/299879) because the actual command issued by qbzr may (?) have the '--exclude .' issue.

I have seen this specific problem only on branches in shared repos. Stand-alone branches seem to be fine, but I have not tested enough to rule that out conclusively.

I have worked successfully with shared repos in the past, but that was with bzr 1.18, qbzr 0.14, bzr-explore 0.7 and python 2.6.2 all on Jaunty. Now I am running bzr 2.0.1, qbzr 0.16, bzr-explore 0.9 and python 2.6.4 on Karmic. So...a lot has changed and I can't make any strong except what I see.