[TxMt] "Add existing files" keyboard shortcut?

[Jay Levitt]

Using 1.5.7 (1464), I realized that the command-shift-A shortcut for Add 
New Files... doesn't work to add files to a project.  I just get a 
system beep.

I've seen no discussion of this here, aside from a 2005 post that said 
it should start working once you've manually displayed the menu, so I'm 
guessing this isn't a common problem.  Yet I'm seeing it on two 
different Macs.   Command-Shift-N, which is on the File menu as well as 
the gear menu, does work. Command-shift-G, which is also on the gear 
menu (and not any other menu), doesn't work either.

Is this in fact a known problem?  Is there a workaround, other than 
QuicKeys/etc?  I took a look at KeyBindings.dict, but I'm not sure if I 
can add command-keystrokes that way, or what the setting would be 
called, etc.

Jay Levitt