Tool bar buttons do not respond while redisplaying?

[Stefan Monnier]

While working on my MPC.el front end to the Music Player Daemon, I noticed
that the tool bar buttons (which I usually don't use) aren't very
responsive, or more specifically, ignore some of my clicks.

This is on GNU/Linux with a default Xaw3d build.

Here is the best way I can describe the behavior I'm seeing:

MPC.el runs a timer every second which polls the MPD daemon (via
a network-process) to know which songs is currently playing, and the time
offset (which is the only thing that changes often enough to justify the 1s
pool interval), and then updates the content of the
mpc-status-buffer accordingly.

If I move the mouse over one of the icons of the toolbar, I see that icon
being "raised", as expected, but every second or so it flickers betwen
raised and not raised.
If I happen to click just when it flickers, the click is ignored.

This doesn't render Emacs unusable, but it makes it feel very flaky :-(


        Stefan