Version:           onbekend (using 4.2.1 (KDE 4.2.1) "release 103", KDE:KDE4:Factory:Desktop / openSUSE_11.0)
Compiler:          gcc
OS:                Linux (i686) release 2.6.25.20-0.1-default

I get a crash of KWin when using Alt-Tab, using 9/10 windows.

Currently open Windows:
- 2x Firefox 3.0.7  (one popup window)
- 4x okular
- 1x konqueror
- 1x kontact
- 1x konsole

The problem no longer seams to occur after I've closed the firefox window.

Programma: KWin (kwin), signaal SIGSEGV
[?1034h[Thread debugging using libthread_db enabled]

Thread 1 (Thread 0xb55b4910 (LWP 23124)):
[KCrash Handler]
#6  0x69746300 in ?? ()
#7  0xb30de795 in KWin::PresentWindowsEffect::rearrangeWindows (this=0x8248410) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.cpp:484
#8  0xb30deeab in KWin::PresentWindowsEffect::setActive (this=0x8248410, active=true, closingTab=false) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.cpp:1153
#9  0xb30df994 in KWin::PresentWindowsEffect::tabBoxAdded (this=0x8248410, mode=2) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.cpp:406
#10 0xb7f9d57f in KWin::EffectsHandlerImpl::tabBoxAdded (this=0x81b3688, mode=2) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects.cpp:291
#11 0xb7f401b5 in KWin::TabBox::show (this=0x8238c60) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/tabbox.cpp:619
#12 0xb7f40245 in KWin::TabBox::qt_metacall (this=0x8238c60, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfde4ce8) at /usr/src/debug/kdebase-workspace-4.2.1/build/kwin/tabbox.moc:65
#13 0xb6ed2740 in QMetaObject::activate (sender=0x8238c8c, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3031
#14 0xb6ed34c2 in QMetaObject::activate (sender=0x8238c8c, m=0xb6fa1904, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3101
#15 0xb6f0dbc7 in QTimer::timeout (this=0x8238c8c) at .moc/release-shared/moc_qtimer.cpp:126
#16 0xb6ed91de in QTimer::timerEvent (this=0x8238c8c, e=0xbfde51d0) at kernel/qtimer.cpp:257
#17 0xb6ecd1ff in QObject::event (this=0x8238c8c, e=0xbfde51d0) at kernel/qobject.cpp:1120
#18 0xb712782c in QApplicationPrivate::notify_helper (this=0x806d0f8, receiver=0x8238c8c, e=0xbfde51d0) at kernel/qapplication.cpp:3803
#19 0xb712f6ce in QApplication::notify (this=0xbfde54d4, receiver=0x8238c8c, e=0xbfde51d0) at kernel/qapplication.cpp:3393
#20 0xb7d2b4ed in KApplication::notify (this=0xbfde54d4, receiver=0x8238c8c, event=0xbfde51d0) at /usr/src/debug/kdelibs-4.2.1/kdeui/kernel/kapplication.cpp:307
#21 0xb7f3a0cd in KWin::Application::notify (this=0xbfde54d4, o=0x8238c8c, e=0xbfde51d0) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/main.cpp:368
#22 0xb6ebda71 in QCoreApplication::notifyInternal (this=0xbfde54d4, receiver=0x8238c8c, event=0xbfde51d0) at kernel/qcoreapplication.cpp:587
#23 0xb6eebde6 in QTimerInfoList::activateTimers (this=0x807002c) at kernel/qcoreapplication.h:209
#24 0xb6ee82b0 in timerSourceDispatch (source=0x806fff8) at kernel/qeventdispatcher_glib.cpp:160
#25 0xb65af2d9 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#26 0xb65b285b in ?? () from /usr/lib/libglib-2.0.so.0
#27 0xb65b29d8 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#28 0xb6ee8208 in QEventDispatcherGlib::processEvents (this=0x804b100, flags={i = -1075948680}) at kernel/qeventdispatcher_glib.cpp:319
#29 0xb71c08c5 in QGuiEventDispatcherGlib::processEvents (this=0x804b100, flags={i = -1075948632}) at kernel/qguieventdispatcher_glib.cpp:198
#30 0xb6ebc14a in QEventLoop::processEvents (this=0xbfde5420, flags={i = -1075948568}) at kernel/qeventloop.cpp:143
#31 0xb6ebc30a in QEventLoop::exec (this=0xbfde5420, flags={i = -1075948504}) at kernel/qeventloop.cpp:194
#32 0xb6ebe9a5 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:845
#33 0xb71276a7 in QApplication::exec () at kernel/qapplication.cpp:3331
#34 0xb7f3cfaa in kdemain (argc=3, argv=0xbfde56a4) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/main.cpp:519
#35 0x08048762 in main (argc=0, argv=0x8317090) at /usr/src/debug/kdebase-workspace-4.2.1/build/kwin/kwin_dummy.cpp:3