Re: how to test whether region is active during a mouse event?

[David De La Harpe Golden]

Drew Adams wrote:

> FWIW -
>
> I never heard of `select-active-regions'. 

It's actually been discussed quite a bit on-list*, though in bursts 
spread over the past couple of years. Its behaviour until recently and 
in the 23.1 branch was flawed.  The various required fixes were a bit 
too involved for the release and are only in trunk, so it was 
intentionally removed (or at least de-documented) from 23.1 just a bit 
before the release [1].

* e.g. Eli Zaretskii just recently raised a couple of issues with the 
initial fixed (see bug #973) implementation now in trunk, I am presently 
attempting to bring up emacs under wine to look more closely at them -
basically (a) making it optionally affect clipboard and (b) making
it a bit less platform-specific in implementation.

> Doc string:
> "If non-nil, an active region automatically becomes the window selection."
>
> I have no idea what the "window-selection" is. And that term is not even used
> anywhere else in the same file that defines it (simple.el). Is it
> described/defined anywhere?

It's pretty close to X11 terminology, though I would have said "window 
system primary selection". Primary? X11 has multiple 
vaguely-clipboard-like entities called "selections", a perennial source 
of confusion.  select-active-regions in conjunction with a few other 
customizations helps emacs optionally largely match one particular 
convention for their use.

primary and select-active-regions are mentioned in the post-23.1 manual, 
at Frames > Cut and Paste > Cut/Paste Other App

> This is a user option. If you really expect users to understand and
> use it,

Only post-23.1...


[1]
http://cvs.savannah.gnu.org/viewvc/emacs/etc/NEWS?view=log&root=emacs&pathrev=EMACS_23_1#rev1.2029.2.3