bug#11588: 24.0.97; Left mouse click setting the mark every time?!??

[Drew Adams]

> The bug in Emacs 23 caused by a slight mouse movement between 
> mouse down and up events that Chong described is quite bad 
> IMHO. Probably worse than a mouse click setting the mark 
> every time. Please don't put that bug back in :-).

Now it's my turn to say I don't understand.

Whether in Emacs 22, 23, or 24, if you move the mouse more than a character
width between down and up then you end up selecting the text you dragged over,
even if it is only one char - and thus highlighting it.  If you then hit `C-w',
the selected text is killed.  C'est normal.

You can _see_ the text to be killed.  That's the point of mouse-selection
highlighting (and the point behind transient-mark-mode highlighting).  If you
don't want to kill the text that you see highlighted, then don't kill it.

I don't understand the problem that the change is designed to fix.  You say that
you hit C-SPC, then you clicked mouse-1 elsewhere but you mistakenly dragged a
bit between button down and up.  OK.  It should have been clear with the
highlighting that the text to be killed did not extend from your C-SPC.  Where
was the mystery?

Sounds like a case of if-it-hurts-don't-do-it.

FWIW, I don't think I have ever mistakenly dragged the mouse slightly between
down and up.  Maybe I've been lucky.

But if some people have that problem then the solution is to do what we do
generally for GUIs (e.g. for double-clicking speed): let users customize the
tolerance for such dragging.  Setting your tolerance greater than one char (e.g.
1.4 chars) would probably take care of your problem.  Of course, if you set it
too high (e.g. 1.6 chars) then you cannot then select a single char with the
mouse...