In Contact Sheet mode you can do a Spotlight search on Macs at the top right. The little drop-down menu to the right of the magnifying glass allows you to turn on or off "only search contact sheet items". However, once turned off, PM resets this to on the next time you run the program (v.4.6.3, Mac OS X 10.5.
. I would like to see a change such that the last setting of this switch is retained between PM sessions.