Version:            (using KDE 4.3.0)
OS:                Linux
Installed from:    SuSE RPMs

Lots of windows were open on three different desktops.
Also, right before the crash the task bar shown incorrect behaviour like in bug 205211, but the crash obviously happens on the different line of code (according to 205211's stacktrace).

This bug may be a duplicate of or related to bug 204093.

Unfortunately, KDE bug reporter failed sending the report, so here's the system information generated:

Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.00 (KDE 4.3.0) "release 158"
Qt Version: 4.5.2
Operating System: Linux 2.6.27.29-0.1-pae i686
Distribution: "openSUSE 11.1 (i586)"

 -- Backtrace:
Application: Рабочее пространство Plasma (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0xb5fb2700 (LWP 3732))]

Thread 2 (Thread 0xa7a1ab90 (LWP 3734)):
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xb7e36c35 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb7e96582 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/libQtCore.so.4
#3  0xb770bad2 in ?? () from /usr/lib/libQtNetwork.so.4
#4  0xb7e95572 in ?? () from /usr/lib/libQtCore.so.4
#5  0xb7e331b5 in start_thread () from /lib/libpthread.so.0
#6  0xb667a3be in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb5fb2700 (LWP 3732)):
[KCrash Handler]
#6  AbstractTaskItem::basicPreferredSize (this=0x9224878) at /usr/src/debug/kdebase-workspace-4.3.0/plasma/applets/tasks/tasks.h:92
#7  0xa830377c in TaskItemLayout::maximumRows (this=0x8537030) at /usr/src/debug/kdebase-workspace-4.3.0/plasma/applets/tasks/taskitemlayout.cpp:185
#8  0xa830cf64 in TaskGroupItem::optimumCapacity (this=0x85b2ca0) at /usr/src/debug/kdebase-workspace-4.3.0/plasma/applets/tasks/taskgroupitem.cpp:1224
#9  0xa82fe5b8 in Tasks::adjustGroupingStrategy (this=0x82ff598) at /usr/src/debug/kdebase-workspace-4.3.0/plasma/applets/tasks/tasks.cpp:241
#10 0xa82fe84c in Tasks::constraintsEvent (this=0x82ff598, constraints={i = -1079572508}) at /usr/src/debug/kdebase-workspace-4.3.0/plasma/applets/tasks/tasks.cpp:165
#11 0xb5d016f0 in Plasma::Applet::flushPendingConstraintsEvents (this=0x82ff598) at /usr/src/debug/kdelibs-4.3.0/plasma/applet.cpp:1163
#12 0xb5d01d98 in Plasma::Applet::timerEvent (this=0x82ff598, event=0xbfa70d00) at /usr/src/debug/kdelibs-4.3.0/plasma/applet.cpp:2110
#13 0xb7f9a72f in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#14 0xb6f8f137 in QGraphicsWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#15 0xb69517fc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#16 0xb6959aee in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#17 0xb744476d in KApplication::notify (this=0x80b8708, receiver=0x82ff598, event=0xbfa70d00) at /usr/src/debug/kdelibs-4.3.0/kdeui/kernel/kapplication.cpp:302
#18 0xb7f8a16b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#19 0xb7fb95f6 in ?? () from /usr/lib/libQtCore.so.4
#20 0xb7fb5980 in ?? () from /usr/lib/libQtCore.so.4
#21 0xb64f7e28 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#22 0xb64fb453 in ?? () from /usr/lib/libglib-2.0.so.0
#23 0xb64fb5d8 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#24 0xb7fb58d8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#25 0xb69f1ce5 in ?? () from /usr/lib/libQtGui.so.4
#26 0xb7f8878a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#27 0xb7f88bd2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#28 0xb7f8b079 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#29 0xb6951677 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#30 0xb3a55b30 in kdemain (argc=1, argv=0x80c4f18) at /usr/src/debug/kdebase-workspace-4.3.0/plasma/shells/desktop/main.cpp:50
#31 0x0804e505 in launch (argc=1, _name=0x809ea94 "/usr/bin/plasma-desktop", args=0x809eaac "", cwd=0x0, envc=0, envs=0x809eab0 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x805163d "0") at /usr/src/debug/kdelibs-4.3.0/kinit/kinit.cpp:705
#32 0x0804ecdd in handle_launcher_request (sock=8, who=<value optimized out>) at /usr/src/debug/kdelibs-4.3.0/kinit/kinit.cpp:1197
#33 0x0804f173 in handle_requests (waitForPid=0) at /usr/src/debug/kdelibs-4.3.0/kinit/kinit.cpp:1390
#34 0x0804feb2 in main (argc=4, argv=0xbfa71944, envp=0xbfa71958) at /usr/src/debug/kdelibs-4.3.0/kinit/kinit.cpp:1825

This bug may be a duplicate of or related to bug 204093