Hi,
Could you tell what window manager you're using when you observe this behavior? Did you try running under Metacity? Is the bug still reproducible then?This was tested under Metacity and it is still a bug.
I just tested this against an old build I had lying around (b12, I believe) and this error does not occur. I have, however, noticed it in at least the last two releases, so it seems to be a regression somewhere between b12 and b15.
Regards, Francis