'<key>' is an unknown key
 
     A request was made to assign a function or macro to a key, but the
     specified key is not recognized by PWB.
 
     This message can appear, for example, if you use an assignment of
     the form:
 
          name:CTRL+SHIFT+key
 
     This combination of keys must be expressed as:
 
          name:SHIFT+CTRL+key
 
     To see the correct syntax for any given key, use the Tell function
     («tell»).
                                    -♦-