On Thu, 2005-06-09 at 10:41 -0400, Richard Stallman wrote:
> The change you've observed is probably due to a change in the code of
> mouse-drag-region. I suggest you look at the code and see what's
> going on.
OK, I've had a look, and think I've figured it out. Aside from the
superficial difference of having split mouse-drag-region into two
functions in 22.0, the real difference actually occurs in `mouse-show-
mark' which is called after all mouse movement events have been
processed, in the code handling the final up-event of the drag.
In 21.3, mouse-show-mark immediately returns if transient-mark-mode is
set:
(defun mouse-show-mark ()
(if transient-mark-mode
(delete-overlay mouse-drag-overlay)
(let ((inhibit-quit t)
....
This allows mouse-drag-region to run to completion. In 22.0, mouse-
show-mark does *not* return immediately:
(defun mouse-show-mark ()
(let ((inhibit-quit t)
(echo-keystrokes 0)
event events key ignore
(x-lost-selection-functions
(when (boundp 'x-lost-selection-functions)
(copy-sequence x-lost-selection-functions))))
(add-hook 'x-lost-selection-functions
(lambda (seltype)
(when (eq seltype 'PRIMARY)
(setq ignore t)
(throw 'mouse-show-mark t))))
(if transient-mark-mode
(delete-overlay mouse-drag-overlay)
(move-overlay mouse-drag-overlay (point) (mark t)))
(catch 'mouse-show-mark
;; In this loop, execute scroll bar and switch-frame events.
;; Should we similarly handle `select-window' events? --Stef
;; Also ignore down-events that are undefined.
(while (progn (setq event (read-event))
....
Instead, it waits for that final read-event, apparently relating to
scrollbar/frame events. So it essentially requires one last non-drag
event (arrow movement, anything), to permit mouse-drag-region to run to
completion.
It *could* be that this is a bug introduced when mouse-show-mark was
rearranged, and what was intended was really:
(if transient-mark-mode
(delete-overlay mouse-drag-overlay)
(move-overlay mouse-drag-overlay (point) (mark t))
(catch 'mouse-show-mark
;; In this loop, execute scroll bar and switch-frame events.
;; Should we similarly handle `select-window' events? --Stef
;; Also ignore down-events that are undefined.
....
i.e. the loop is never entered and read-event is never called, if
transient-mark-mode is set. This trivial fix gives me the behavior I
want, but since I don't know enough about these functions to understand
if this was intended behavior or not, I'd appreciate your feedback.
Here is the relevant change log comment:
revision 1.252
date: 2004/10/27 17:44:59; author: rms; state: Exp; lines: +49 -48
(mouse-show-mark): Do most processing the same
regardless of transient-mark-mode.
>From the comment it does seem intended.
JD
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