Thanks for the prompt reply, much appreciated.

Finding a (possible) bug in the first week of using a major application is a
new personal record for me :-)

Anyhow, I think mouse events not making it quite through to where they
should be noted is nothing unheard of -- what really worries me that this
affects only *single* clicks, whereas double-clicks work just fine, as does
dragging.

Or may be I should not have named my agent class "Bug" in place of the
original "Student"? (It's going to be a biology simulation.) 
:-)

OK; I'll keep checking the Repository for updates.
Thanks again, and good luck.

Cheers,
Martin