RE: mouse-yank-primary and bug #7699

[Drew Adams]

> > And the proviso about "same session" signifies a difference that
> > should also be pointed out as part of the description.
> 
> That could be in the manual, but I see no good way of documenting this
> in the doc strings.  There's any number of functions and variables
> related to selections; saying this in all of them seems a bad idea,
> while saying just in some would not solve the problem.

I agree; the manual's the place.

The description of all of this stuff in the manual will need some work, once the
behavior is finalized.  It might not be easy to make it both readable and
comprehensive, but that's the challenge.