Macintosh OS X 10.6.7 update addresses Photoshop sticky modifier key issue
We’ve heard a common challenge Macintosh users are facing when using Photoshop is that it behaves as if the option or shift key is selected. Good news is that Apple released the 10.6.7 update for OS X today. This update addresses the issue in the 10.6.5 update that affected modifier keys while using Photoshop.
More details, including how to install the update, are available in this Knowledge Base document: Alert