region not set before mouse-up

[David Reitter]

When a region is selected but the mouse-1 is not yet 'up', the region  
content cannot be copied or modified. For example, when clipboard-  
kill-ring-save is called in that state, the region highlighting is  
removed, but the content of the region is not copied to the  
clipboard. Typical events:

<down-mouse-1> <mouse-movement> <mouse-movement> H-c <help-echo>  
<help-echo>

(H-c is bound to clipboard-kill-ring-save in my setup.)
In the control case, when everything works ok (mouse-1 goes up before  
H-c), one gets an extra <drag-mouse-1> event, which calls mouse-set-  
region.

One may wonder: who would do such a funny thing like keeping one  
finger on the mouse button and then pressing some keys to do  
something with the region, unless they are desperately looking for  
obscure bugs in Emacs.

But as a matter of fact, my system offers the option to modify the  
trackpad behavior so I can drag things with a click at the beginning,  
and a click at the end. This setting is useful with common laptop  
trackpads (especially if you remap the only mouse button they  
offer!), and such a feature is used by people with certain motor  
impairments, i.e. disabled users. Pretty often, I would select  
something, but don't apply the second click. Then, a visual selection  
exists (presumably marking a region), but obviously Emacs has trouble  
doing the things it usually does with regions...

From a UI perspective, the user sees a highlighted region (and  
doesn't know about the mouse state) and wonders why it doesn't behave  
like any other highlighted region. That is inconsistent.



(Sorry: repeat-posting, this time with useful subject line)



In GNU Emacs 22.0.50.3 (powerpc-apple-darwin8.1.0)
 of 2005-05-23 on madonna - Aquamacs Distribution 0.9.2 beta-4
Distributor `Apple Computers' version (10 4 1) .
configured using `configure '--without-x' '--prefix=/usr/local''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  show-paren-mode: t
  delete-selection-mode: t
  pc-selection-mode: t
  cua-mode: t
  recentf-mode: t
  encoded-kbd-mode: t
  osx-key-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  tooltip-mode: t
  auto-compression-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  next-error-follow-minor-mode:  Fol

Recent input:
s <tab> i e <tab> <return> <down-mouse-1> <mouse-1> H-w <switch-  
frame> <down-mouse-1> <mouse-movement> <mouse-movement> <down> <drag-  
mouse-1> <down> <down-mouse-1> <mouse-1> <double-down-mouse-1>  
<double-mouse-1> <down-mouse-1> <mouse-movement> <mouse-movement>  
<drag-mouse-1> <left> <left> <down-mouse-1> <mouse-movement> <mouse-  
movement> <drag-mouse-1> <right> <right> <down-mouse-1> <mouse-1>  
<double-down-mouse-1> <double-mouse-1> <down-mouse-1> <mouse-  
movement> <mouse-movement> <drag-mouse-1> <down-mouse-1> <mouse-1>  
<down-mouse-1> <mouse-movement> <mouse-movement> SPC <drag-mouse-1>  
<down-mouse-1> <mouse-1> <switch-frame> <switch-frame> C-h k H-c  
<down-mouse-1> <mouse-movement> <mouse-movement> <drag-mouse-1>  
<down- mouse-1> <mouse-1> <double-down-mouse-1> <mouse-movement>  
<mouse- movement> <double-drag-mouse-1> H-c H-w <switch-frame>  
<switch-frame> <down-mouse-1> <mouse-movement> <mouse-1> <down- 
mouse-1> <mouse-1> <down-mouse-1> <mouse-movement> <mouse-movement>  
<drag-mouse-1> H-c <down-mouse-1> <mouse-1> <down-mouse-1> <mouse- 
movement> <mouse- movement> <drag-mouse-1> <down-mouse-1> <mouse- 
movement> <mouse- movement> <drag-mouse-1> H-c <down-mouse-1>  
<mouse-1> <down-mouse-1> <mouse-movement> <mouse-movement> H-c <help- 
echo> <help-echo> <menu- bar> <help-menu> <report-emacs-bug>

Recent messages:
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Loading sgml-mode...done
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Making completion list...
t
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