non-numeric input 
The Type number(s): prompt expects a numeric response, and that makes sense, but I can think of other things that would be handy instead, based on a small set of leading keywords, or option flags.

keywords;
   all - selects "all" available choices (like -b after-the-fact)

flags; 
   if, at the taskopen prompt, you could enter a flag, or set of flags, and taskopen would then re-run the previous command with the new flags, that would allow quick variations.
(see #48 command history)
