[xmonad] Firefox redraw

[Tuncer Ayaz]

The recent urxvt slow rendering thread reminded me that xmonad
sometimes suffers from an interesting redraw slowdown with Firefox
that doesn't happen in dwm or spectrwm.

Sometimes Firefox as the sole window in a tag/desk takes longer to
redraw itself upon entering the tag/desk when the previous tag/desk
was an empty one. If you switch from a tag/desk with one or more
windows, then it's quicker to redraw. Put differently, you either
notice the redraw or you don't. I say sometimes because I haven't been
able to reproduce it today, but I wonder if anyone else has seen this.
The config is xmonad-testing/example-config.hs or my extended version
with personalized settings, and I use compton to enable vsync, if that
matters.