In Zimbra Desktop 2.0, is there any way to actually modify the shortcuts?

I can click Preferences, then Shortcuts under my "All Accounts" section, and it brings up the list of Shortcuts with a "Save" or "Cancel" option.

Yet, there appears to be no way to actually change or modify these.
Am I missing something, or is this functionality just missing?

Any help is much appreciated, thanks.

Richard