[xmonad] Problem with xmonad and rendering Dolphin windows in KDE

[Leo Alekseyev]

I recently made the switch to KDE (Kubuntu 12.04, to be precise);
xmonad works very well with it, except for one thing: Dolphin windows
take a rather long time to render compared to other applications.  By
that I mean that if I switch to a desktop which has Dolphin windows
visible, the Dolphin windows will show as grey background for about
2-3 seconds, before being rendered properly.  Right afterwards,
switching between the "Dolphin" desktop and another desktop is rather
fast (Dolphin renders quickly).  But if I stay on a different desktop
for more than about 1 minute and then switch back to the "Dolphin"
desktop, I'll see the 2-3 second delay again.  This behavior seems
exclusive to Dolphin (other Qt apps and GTK apps seem to work fine).
If other KDE users on the list have seen this behavior and/or can
suggest any remedies, I would be interested in hearing about it!

--Leo