Version:           unknown (using KDE 3.3.89 (CVS >= 20040820), compiled sources)
Compiler:          gcc version 3.3.4 20040623 (Gentoo Linux 3.3.4-r1, ssp-3.3.2-2, pie-8.7.6)
OS:                Linux (i686) release 2.6.7-gentoo-r9

- Select the Plastik window decoration (any window decoration that handles font changes without a hard reset should do it as well)
- Make one window shaded
- Use KControl to change the window title font size

KWin crashes with this output on stderr:
kwin: User timestamp, initial:19163254
kwin: User timestamp, ASN:19163254
kwin: User timestamp, final:'ID:20971525;WMCLASS:kicker:kicker;Caption:kicker':19163254
kwin: Activation: No client active, allowing
kwin: User timestamp, initial:19206032
kwin: User timestamp, ASN:19206032
kwin: User timestamp, final:'ID:16783713;WMCLASS:kcontrol:kcontrol;Caption:Select Font - Control Center':19206032
kwin: Activation: Belongs to active application
kwin: Workspace::slotReconfigure()
kwin: h:380:t:24:b:4
kwin: /home/sandro/src/kde/kdebase/kwin/geometry.cpp:1644: void KWinInternal::Client::plainResize(int, int, KWinInternal::ForceGeometry_t): Assertion `false' failed.
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kwin path = <unknown> pid = 11652

Backtrace:
Using host libthread_db library "/lib/libthread_db.so.1".
[KCrash handler]
#5  0x4123b841 in kill () from /lib/libc.so.6
#6  0x410ccba0 in pthread_kill () from /lib/libpthread.so.0
#7  0x410ccefb in raise () from /lib/libpthread.so.0
#8  0x4123b422 in raise () from /lib/libc.so.6
#9  0x4123cc9c in abort () from /lib/libc.so.6
#10 0x41234889 in __assert_fail () from /lib/libc.so.6
#11 0x400848c8 in KWinInternal::Client::plainResize(int, int, KWinInternal::ForceGeometry_t) (this=0x80e4458, w=971, h=836, force=ForceGeometrySet)
    at /home/sandro/src/kde/kdebase/kwin/geometry.cpp:1644
#12 0x4004999b in KWinInternal::Client::checkBorderSizes() (this=0x80e4458)
    at qsize.h:132
#13 0x4004012d in KWinInternal::Workspace::slotReconfigure() (this=0x80c8e40)
    at /home/sandro/src/kde/kdebase/kwin/workspace.cpp:760
#14 0x4004631d in KWinInternal::Workspace::qt_invoke(int, QUObject*) (
    this=0x80c8e40, _id=51, _o=0xbfffec60) at workspace.moc:285
#15 0x4099d1f9 in QObject::activate_signal(QConnectionList*, QUObject*) (
    this=0xbffff1d0, clist=0x80ec218, o=0xbfffec60) at kernel/qobject.cpp:2357
#16 0x4099d099 in QObject::activate_signal(int) (this=0xbffff1d0, signal=8)
    at kernel/qobject.cpp:2326
#17 0x404403de in KApplication::appearanceChanged() (this=0x0)
    at qmetaobject.h:261
#18 0x404370be in KApplication::kdisplaySetFont() (this=0xbffff1d0)
    at /home/sandro/src/kde/kdelibs/kdecore/kapplication.cpp:2062
#19 0x40435420 in KApplication::x11EventFilter(_XEvent*) (this=0xbffff1d0, 
    _event=0x0) at /home/sandro/src/kde/kdelibs/kdecore/kapplication.cpp:1751
#20 0x40058472 in KWinInternal::Application::x11EventFilter(_XEvent*) (
    this=0x0, e=0xbffff070) at /home/sandro/src/kde/kdebase/kwin/main.cpp:155
#21 0x408bc68d in qt_x11EventFilter (ev=0xbffff070)
    at kernel/qapplication_x11.cpp:386
#22 0x408c5ced in QApplication::x11ProcessEvent(_XEvent*) (this=0xbffff1d0, 
    event=0xbffff070) at kernel/qapplication_x11.cpp:3305
#23 0x408e0903 in QEventLoop::processEvents(unsigned) (this=0x8077ab8, flags=4)
    at kernel/qeventloop_x11.cpp:192
#24 0x4094e5bd in QEventLoop::enterLoop() (this=0x8077ab8)
    at kernel/qeventloop.cpp:198
#25 0x4094e4d6 in QEventLoop::exec() (this=0x8077ab8)
    at kernel/qeventloop.cpp:145
#26 0x4093a231 in QApplication::exec() (this=0xbffff1d0)
    at kernel/qapplication.cpp:2758
#27 0x400588b8 in kdemain (argc=2, argv=0xbffff3e4)
    at /home/sandro/src/kde/kdebase/kwin/main.cpp:281
#28 0x0804872b in main (argc=0, argv=0x0) at kwin.la.cpp:2