This thread just gave me an idea... Does anyone who has written an applet/otherwise has knowledge, know if an applet can move itself? If so, a given applet (an open-source one) could have a configuration setting added in which it jumps back to its home after being moved.

OTOH, someone would undoubtedly have taken advantage of it by now and made an applet which roams around the screen, or dodges when it thinks you're getting ready to hit it, or some other useful behaviour, so I guess it must not be possible.