Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.3 (KDE 4.3.3)
Qt Version: 4.5.3
Operating System: Linux 2.6.31-ARCH x86_64

What I was doing when the application crashed:
I was switching workspaces, and the contents of the task manager froze. When I right-clicked the task manager, the plasma desktop crashed.

I tried to reproduce the crash, but didn't succeed.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f0b757b0760 (LWP 4099))]

Thread 2 (Thread 0x7f0b561b7710 (LWP 4280)):
#0  0x00007f0b74f9d07c in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f0b75208c6b in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/libQtCore.so.4
#2  0x00007f0b71683c9c in ?? () from /usr/lib/libQtNetwork.so.4
#3  0x00007f0b75207ba5 in ?? () from /usr/lib/libQtCore.so.4
#4  0x00007f0b74f9881a in start_thread () from /lib/libpthread.so.0
#5  0x00007f0b729618cd in clone () from /lib/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f0b757b0760 (LWP 4099)):
[KCrash Handler]
#5  0x00007f0b73605dc4 in QGraphicsItem::isWidget() const () from /usr/lib/libQtGui.so.4
#6  0x00007f0b736084f9 in QGraphicsItem::isWindow() const () from /usr/lib/libQtGui.so.4
#7  0x00007f0b7363bc49 in QGraphicsScene::event(QEvent*) () from /usr/lib/libQtGui.so.4
#8  0x00007f0b7308807c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#9  0x00007f0b7308f34e in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#10 0x00007f0b73cbb8f6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#11 0x00007f0b752ecbfc in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#12 0x00007f0b7364d3f6 in QGraphicsView::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4
#13 0x00007f0b752ebf47 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#14 0x00007f0b7308804c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#15 0x00007f0b7308f34e in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#16 0x00007f0b73cbb8f6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#17 0x00007f0b752ecbfc in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#18 0x00007f0b730d6c7b in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#19 0x00007f0b7342fd26 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4
#20 0x00007f0b734bea59 in QAbstractScrollArea::event(QEvent*) () from /usr/lib/libQtGui.so.4
#21 0x00007f0b7308807c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#22 0x00007f0b7308f34e in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#23 0x00007f0b73cbb8f6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#24 0x00007f0b752ecbfc in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#25 0x00007f0b730926db in QApplication::setActiveWindow(QWidget*) () from /usr/lib/libQtGui.so.4
#26 0x00007f0b730f3bbe in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#27 0x00007f0b7311b96c in ?? () from /usr/lib/libQtGui.so.4
#28 0x00007f0b71fe81fe in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#29 0x00007f0b71febbb8 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#30 0x00007f0b71febce0 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#31 0x00007f0b75315123 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#32 0x00007f0b7311b14e in ?? () from /usr/lib/libQtGui.so.4
#33 0x00007f0b752eb532 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#34 0x00007f0b752eb904 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#35 0x00007f0b752edab9 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#36 0x00007f0b6910928f in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#37 0x0000000000406eae in _start ()

Reported using DrKonqi