I run Tiger on the iMac, Panther on the iBook. I came across this old article by chance, and was amazed about the things I didn't know: Macworld: Feature: Panther Secrets Declassified. The Mac is like that, full of odd abilities.
BTW, the old hack for enabling hidden calculator views in Panther doesn't seem to work any more, I wonder if some Panther upgrade broke it. The hidden views display as silvery metallic windows. These were never officially supported, so I can't complain too much. It does make me want to look again at Tiger's calculatory though.