bug#19513: shift-select-mode fails to be fully buffer-local

[Stefan Monnier]

> Comment out lines 384-385 to enable it to work with shift-select-mode, to see 
> how the latter interferes.
> Enable the mode, then press S-down.  Then press down, and since you're
> doing a non-shifted motion command following a shifted motion command,
> shift-select-mode deactivates the region.

I'm not sure it should be considered as a bug, or at least one specific
to line-select-minor-mode.

The same behavior shows up if you do (in "emacs -Q"):

  C-SPC next S-next

and you see that the S-next ended the previous selection and started
a new one.  Some might see it as a feature (I don't know if it was
implemented this way on purpose or by accident).

If we see it as a bug the right answer is probably to change
shift-select-mode such that shifted-motion doesn't start a new
shift-selection if we're already in the middle of an
"old-style" selection.

Since you have shift-select-mode disabled globally, you shouldn't
care anyway, so I guess you're doing this in response to complaints from
users of vimizer.  If so, do they usually use shift-select-mode?
If not, maybe the right answer is to tell them they should disable
shift-select-mode.


        Stefan