Certain keyboard function keys do NOT send anything to
   the computer. Thus NONE of the following should be used
   as part of a hot-key string: F2, F3, F4, F5.

   In addition, there are certain keys which do NOT have a
   CTRL value associated with them. The numeric keys are like
   this, as are many of the punctuation and keypad keys.

   Here is a list of ILLEGAL key definitions:

         CTRL-0  CTRL-1  CTRL-2  CTRL-3  CTRL-4  CTRL-5  CTRL-6
         CTRL-7  CTRL-8  CTRL-9  CTRL-!  CTRL-@  CTRL-#  CTRL-$
         CTRL-%  CTRL-&  CTRL-*  CTRL-(  CTRL-)  CTRL--  CTRL-+
         CTRL-=  CTRL-.  CTRL-,  CTRL-> CTRL-<