Re: use of `mouse-face' to delimit text zones

[Eli Zaretskii]

> From: Stefan Monnier <address@hidden>
> Cc: Drew Adams <address@hidden>,  address@hidden,  address@hidden
> Date: Tue, 23 Aug 2011 14:34:25 -0400
> 
> > How is Joe R. Hacker supposed to know that adding invisible characters
> > to a portion of text covered by mouse-face will break completion??
> 
> We're talking about a property added *by the completion code* and *for
> the completion code*.  I.e. an internal use.

Not entirely true: when the mouse hovers above those parts of the
*Completions* buffer, the candidate under the mouse gets highlighted.
By contrast, a face added for internal purposed would be invisible to
the user.

> Joe R. Hacker doesn't need to know about it unless he actually hacks
> on the code that handles minibuffer-completion-help.

Guess what? he just did.