Mac OS X 10.4 introduced some confusion about how Option-Command-T should be used; the Human Interface Guidelines recommend it for toggling the display of toolbars, but it is bound to the Character Palette by default.
From the Apple Human Interface Guidelines:
Here is what it is, by default, assigned to in Mac OS X 10.4:
This obviously isn’t a problem if an application has no toolbar, but it should be automatically bound if the application uses a standard Cocoa toolbar.
Developers, you may want to bookmark the Keyboard Shortcuts Quick Reference.
