RE: Should the mode line extend under the scroll bar?

[Drew Adams]

Good point. I agree that some visual means of associating the scroll bar
with its window might be a good thing.

We don't have to lump the two issues together though, and decide whether
Emacs 20 or 21 is better in this regard. We can perhaps DTRT by combining
your point with mine:

 1. Make the drag-handle affordance visible. Give some space and maybe a
graphic that indicates what it's for (e.g. the drag-handle cursor glyph).

 2. Visually associate the scroll bar with its window (not necessarily the
window's mode line.

Your point about mode-line sensitivity under the scroll bar (that is, where
the drag handle is) is precisely my second point - vertical bar dragging
should be disassociated from mode-line activation (sensitivity). This
interference is an unpleasant side effect.

So, the questions are, IMO:

 - How best to visually associate the scroll bar with its window in such a
way that this association does not interfere with vertical-line dragging?
 - How to dissociate mode-line activation (sensitivity) from vertical-line
dragging?

A drag handle "some pixels wider" is maybe a solution, but we can perhaps do
better. How successful this solution would be would need to be tested - it
depends on how small the drag-handle area is, and how easily the mode-line
sensitivity still interferes with vertical-line dragging.

If a good solution doesn't occur to us - that is, if we're ultimately forced
to choose between the two desirables #1 and #2 above, then I would choose
#1. Why? Because the scroll bar is obvious; the drag handle is not obvious.

Just trying the scroll bar out is enough to quickly teach you which window
it belongs to (though I hear your point about 21.4 and diff windows having
diff scroll-bar positions). The scroll bar is there; just try it to see
which window is affected. Without adequate real estate (and perhaps a
drag-handle graphic), however, the _existence_ of the drag handle can be
_missed entirely_.

Also, I don't think that extending the mode line under the scroll bar is a
good way to associate the two (or, what's really wanted, to associate the
scroll bar with the window). There must be a better way (if one is needed).


From: Kim F. Storm

> Emacs 20:                 Emacs 21:
>        M       M                 M       M
> XXXXXXX.ZZZZZZZ.          XXXXXXXXZZZZZZZZ
>
> The squares where the `.' are were visible drag handles for the windows.

IMO the emacs 21 display behaviour is better as it indicates which
window the scroll bar belongs to.  This is more important with 21.4
where each window can control the position of its own scrollbar
(left/right).

However, I do think we can make the grab area some pixels wider
without too much trouble.  However, now since the modeline does extend
under the scrollbar, there may be mouse-sensitive elements on the
modeline at those positions, so we should be careful not to disrupt
the access to those elements (especially when the scrollbar is on the
left side).