redisplay flicker

[Dave Love]

[In Emacs 21.1, as modified by Debian.]

I have a buffer (*compilation*) full of overlays in a remote-running
Emacs (Debian testing) displayed under X (Debian stable) over a 10Mb
network link which probably isn't very busy.  The display flickers
annoyingly.  When the frame gets the focus it's worse -- the overlay
under the mouse positively throbs.

I don't see the same with a local display, so I assume it's due to
network bandwidth and that it would be worse over a slower network.

This turns out to be a function of blink-cursor mode.  Turning that
off stops the flicker.  I don't know why this hasn't bothered me
before...