Version:            (using KDE KDE 3.5.2)
Installed from:    Compiled From Sources
Compiler:          gcc version 3.4.5 20051201 (Red Hat 3.4.5-2) 
OS:                Linux

kwin suddeny crashed when I clicked on firefox window to move it. There was no history of kwin problems through several months of continuous operation until this happened. Backtrace is included below.

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Using host libthread_db library "/lib/tls/libthread_db.so.1".
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[Thread debugging using libthread_db enabled]
[New Thread -1232767264 (LWP 7938)]
[KCrash handler]
#6  0xb64b407c in KWinInternal::Workspace::nextFocusChainClient ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#7  0xb64c70a5 in KWinInternal::TabBox::createClientList ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#8  0xb64c8a07 in KWinInternal::TabBox::reset ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#9  0xb64c9368 in KWinInternal::Workspace::startKDEWalkThroughWindows ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#10 0xb64e1e74 in KWinInternal::Workspace::slotWalkThroughWindows ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#11 0xb64eaca9 in KWinInternal::Workspace::qt_invoke ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#12 0xb7829f32 in KGlobalAccelPrivate::activate ()
   from /home/yan/data/kde3.5.2/lib/libkdecore.so.4
#13 0xb789baec in KGlobalAccelPrivate::x11KeyPress ()
   from /home/yan/data/kde3.5.2/lib/libkdecore.so.4
#14 0xb789be86 in KGlobalAccelPrivate::x11Event ()
   from /home/yan/data/kde3.5.2/lib/libkdecore.so.4
#15 0xb7894338 in KApplication::x11EventFilter ()
   from /home/yan/data/kde3.5.2/lib/libkdecore.so.4
#16 0xb64ee288 in KWinInternal::Application::x11EventFilter ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#17 0xb7160505 in qt_set_x11_event_filter ()
   from /home/yan/data/kde3.5.2/lib/libqt-mt.so.3
#18 0xb716c5f8 in QApplication::x11ProcessEvent ()
   from /home/yan/data/kde3.5.2/lib/libqt-mt.so.3
#19 0xb717e8cc in QEventLoop::processEvents ()
   from /home/yan/data/kde3.5.2/lib/libqt-mt.so.3
#20 0xb71e07c3 in QEventLoop::enterLoop ()
   from /home/yan/data/kde3.5.2/lib/libqt-mt.so.3
#21 0xb71e0720 in QEventLoop::exec ()
   from /home/yan/data/kde3.5.2/lib/libqt-mt.so.3
#22 0xb71cb92c in QApplication::exec ()
   from /home/yan/data/kde3.5.2/lib/libqt-mt.so.3
#23 0xb64ef959 in kdemain ()
   from /home/yan/data/kde3.5.2/lib/libkdeinit_kwin.so
#24 0xb7c4f6e6 in kdeinitmain () from /home/yan/data/kde3.5.2/lib/kde3/kwin.so
#25 0x0804e339 in launch ()
#26 0x0804ea9a in handle_launcher_request ()
#27 0x0804f037 in handle_requests ()
#28 0x0804f7ab in main ()