Version:           4.1.80 (using Devel)
OS:                Linux
Installed from:    Compiled sources

I just clicked on the Kopete icon to let it show my contact list which resulted in a crash of kwin with the following backtrace:

Anwendung: KWin (kwin), Signal SIGABRT

Thread 1 (Thread 0xb64126c0 (LWP 6932)):
[KCrash Handler]
#6  0xb7f76430 in __kernel_vsyscall ()
#7  0xb6826880 in raise () from /lib/tls/i686/cmov/libc.so.6
#8  0xb6828248 in abort () from /lib/tls/i686/cmov/libc.so.6
#9  0xb7591795 in qt_message_output () from /usr/lib/libQtCore.so.4
#10 0xb7591872 in qFatal () from /usr/lib/libQtCore.so.4
#11 0xb75918cc in qt_assert_x () from /usr/lib/libQtCore.so.4
#12 0xb7ef3b6a in KWin::Workspace::clientArea (this=0x9d41250, opt=KWin::FullArea, screen=-1, desktop=1) at /usr/include/qt4/QtCore/qvector.h:321
#13 0xb7ef3dff in KWin::Workspace::clientArea (this=0x9d41250, opt=KWin::FullArea, p=@0xbff77998, desktop=1) at /build/buildd/kdebase-workspace-4.1.80/kwin/geometry.cpp:279
#14 0xb7f0a172 in KWin::Unmanaged::shouldUnredirect (this=0xa04ba98) at /build/buildd/kdebase-workspace-4.1.80/kwin/composite.cpp:911
#15 0xb7f0e895 in KWin::Toplevel::updateUnredirectedState (this=0xa04ba98) at /build/buildd/kdebase-workspace-4.1.80/kwin/composite.cpp:833
#16 0xb7f0ee2a in KWin::Workspace::delayedCheckUnredirect (this=0x9d41250) at /build/buildd/kdebase-workspace-4.1.80/kwin/composite.cpp:602
#17 0xb7ea5e66 in KWin::Workspace::qt_metacall (this=0x9d41250, _c=QMetaObject::InvokeMetaMethod, _id=144, _a=0xbff77b68)
    at /build/buildd/kdebase-workspace-4.1.80/obj-i486-linux-gnu/kwin/workspace.moc:447
#18 0xb769ea60 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#19 0xb769f7e2 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#20 0xb76d97a7 in QTimer::timeout () from /usr/lib/libQtCore.so.4
#21 0xb76a540e in QTimer::timerEvent () from /usr/lib/libQtCore.so.4
#22 0xb769953f in QObject::event () from /usr/lib/libQtCore.so.4
#23 0xb6d7a8ec in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#24 0xb6d8272e in QApplication::notify () from /usr/lib/libQtGui.so.4
#25 0xb7c91c6d in KApplication::notify (this=0xbff782f4, receiver=0x9d414e0, event=0xbff7801c) at /build/buildd/kde4libs-4.1.80/kdeui/kernel/kapplication.cpp:307
#26 0xb7ebdbdd in KWin::Application::notify (this=0xbff782f4, o=0x9d414e0, e=0xbff7801c) at /build/buildd/kdebase-workspace-4.1.80/kwin/main.cpp:371
#27 0xb7689e61 in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#28 0xb76b7d81 in ?? () from /usr/lib/libQtCore.so.4
#29 0xb76b4520 in ?? () from /usr/lib/libQtCore.so.4
#30 0xb66226f8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#31 0xb6625da3 in ?? () from /usr/lib/libglib-2.0.so.0
#32 0xb6625f61 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#33 0xb76b4478 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#34 0xb6e14ea5 in ?? () from /usr/lib/libQtGui.so.4
#35 0xb768852a in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#36 0xb76886ea in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#37 0xb768ada5 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#38 0xb6d7a767 in QApplication::exec () from /usr/lib/libQtGui.so.4
#39 0xb7ec1b8e in kdemain (argc=3, argv=0xbff784c4) at /build/buildd/kdebase-workspace-4.1.80/kwin/main.cpp:513
#40 0x08048742 in main (argc=) at /build/buildd/kdebase-workspace-4.1.80/obj-i486-linux-gnu/kwin/kwin_dummy.cpp:3

I cannot reproduce this bug and I am not sure whether or not this is related to the action I did with the Kopete icon or not. I mainly wanted you to know the backtrace so you may be able to spot the bug in the code.