Re: Tool bar buttons stay active too long

[Eli Zaretskii]

On Sun, 6 Jan 2002, Richard Stallman wrote:

> I find that a tool bar button will often stay highlighted
> after I move the mouse up thru the tool bar into the menu bar.
> I observed this specifically with the first two buttons in the
> default tool bar.
> 
> Sometimes while I move the mouse very slightly in the menu bar
> around the File and Edit items, the tool bar button below
> will flicker between the active and inactive states.

I had similar (although not identical) experiences.  During the last 
phases of the pretest, I reported a few problems to Gerd.  Gerd made
some changes and things started to work more smoothly.  But I still find 
that tooltips flicker in some rare cases.

I think all these flickerings are a ``feature'' of the redisplay that 
Emacs decides to perform: each such redisplay first resets the buttons to 
their inactive state, then raises them again.  This is based on a vague 
recollection from reading the code long ago, though; Gerd, am I right 
about this?

If I'm right, then the solution would be either avoid the redisplay in 
some of the cases we don't now, or change the way redisplay handles 
buttons and tips.  I'm not sure the latter is possible or feasible.

Note that I don't have the CVS version built for X toolkit anywhere where 
I work, so what I know is limited to the stock v21.1 and its pretests.

> I think that Gerd or Eliz is the person who knows this code.
> Is that right?

I cannot say that I know this code to the degree where I can debug it 
efficiently.  One problem with these issues is that apparently different 
platforms somehow have differences in events reported by the toolkit to 
Emacs.  For example, when I click the mouse once on the scroll-bar arrow, 
Emacs gets 2 or more scroll events on my system, while Gerd sees only one 
on his; IIRC, we had similar diffirences for tooltips and tool-bar 
buttons back when I tried to debug these problems.  Unfortunately, I 
don't know enough about X and the toolkit to hypothesize what could be 
the reason for those differences.

Btw, as long as we are talking about display flickering, one problem 
which annoys me is what happens in Customize buffers.  More often than 
not, the 3D buttons there start ``breathing'': they all raise and lower 
themselves at approximately 1-sec cycle, especially after I move the mouse 
pointer above one of the buttons.  Clicking the mouse on something in the 
buffer would usually stop that ``breathing''.