Version:            (using Devel)
Compiler:          gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)  Target: i486-linux-gnu 
OS:                Linux
Installed from:    Compiled sources

The problem happens most often when i switch from some other window to firefox.  It will only paint portions of the window that have certain widgets like buttons, generally near where the mouse is.  To be able to view the whole program, i have to "clean" everything by moving my mouse over it.  Once the mouse hits a widget that does some kind of appearance change upon mouseover, that section of the window will be redrawn.  The kwin titlebar of the window will also fail to draw, and to see it i usually have to drag the window.

So far this has happened with Firefox, emacs, anki (which uses qt 4.4), and maybe a few others.  The problem is commonly triggered when i switch from a terminal window to firefox, but that might just reflect my usage patterns of switching from irc (in a terminal) to firefox.

The problem is difficult to reproduce consistently.  Once i get out the ksnapshot program then suddenly i can't make it happen again ;)

I'm using composite settings on an Intel card.
from lspci:
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)

This problem only showed up some time during the past two weeks.  I compiled from the latest svn in late august and it was fine, no problems.  i later upgraded from svn in september and the problem started.  I tried svn from around sept 21 and the problem still appeared.

from Xorg.log:
(II) LoadModule: "intel"
(II) Loading /usr/lib/xorg/modules/drivers//intel_drv.so
(II) Module intel: vendor="X.Org Foundation"
        compiled for 1.4.0.90, module version = 2.2.1
        Module class: X.Org Video Driver
        ABI class: X.Org Video Driver, version 2.0


$ uname -a
Linux steller 2.6.24-18-generic #1 SMP Wed May 28 20:27:26 UTC 2008 i686 GNU/Linux

My distro is Ubuntu Hardy.  All portions of kde, qt, kdesupport, etc are from svn.  I rebuilt them entirely last week in order to see if the bug would go away.

Please let me know if there's more information you'd like, or if there's a specific version you'd like me to check out of svn and compile.  Here's what i'm using currently:

plypkie@steller:~/kde/src/KDE/kdebase$ svn info
Path: .
URL: svn://anonsvn.kde.org/home/kde/trunk/KDE/kdebase
Repository Root: svn://anonsvn.kde.org/home/kde
Repository UUID: 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
Revision: 862836
Node Kind: directory
Schedule: normal
Last Changed Author: aseigo
Last Changed Rev: 862833
Last Changed Date: 2008-09-19 18:03:30 -0700 (Fri, 19 Sep 2008)