In response to Bart Schaefer's message 
http://www.zsh.org/mla/users/2017/msg00331.html

I've tried what you described, and also added a colour for the non-match 
part ... that gets even more fun, because the colour shows up for the 
option that contains the match, but not others:
https://cloud.githubusercontent.com/assets/168694/25104671/85b5e3fe-23c1-11e7-9b3d-2b65352ff06c.png


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Sorry, his response came in before I had confirmed my mail address for 
this mailing list. I didn't get his response via mail, and thus can't 
properly reply to it.