Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31.1-56.fc12.i686 i686
Distribution: "Fedora release 11.92 (Rawhide)"

What I was doing when the application crashed:
I double-clicked to open the calendar widget I had installed in the panel. When I did, the plasma workspace crashed. 

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0xb801f7a0 (LWP 2173))]

Thread 2 (Thread 0xacebbb70 (LWP 2174)):
#0  0x00dca416 in __kernel_vsyscall ()
#1  0x00c190d5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0x035fc4ef in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/libQtCore.so.4
#3  0x0386ee22 in ?? () from /usr/lib/libQtNetwork.so.4
#4  0x035fb473 in ?? () from /usr/lib/libQtCore.so.4
#5  0x00c149d5 in start_thread () from /lib/libpthread.so.0
#6  0x00b6786e in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb801f7a0 (LWP 2173)):
[KCrash Handler]
#6  0x042c1f9a in QGraphicsItem::isWidget() const () from /usr/lib/libQtGui.so.4
#7  0x042c4e43 in QGraphicsItem::isWindow() const () from /usr/lib/libQtGui.so.4
#8  0x042fb26f in QGraphicsScene::event(QEvent*) () from /usr/lib/libQtGui.so.4
#9  0x03cbeba4 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#10 0x03cc62f9 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#11 0x047ad52b in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#12 0x036eccc3 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#13 0x0430c487 in QGraphicsView::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4
#14 0x04163295 in ?? () from /usr/lib/libQtGui.so.4
#15 0x036ebe1a in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#16 0x03cbeb7d in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#17 0x03cc624b in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#18 0x047ad52b in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#19 0x036eccc3 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#20 0x03d13a6d in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#21 0x040c1604 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4
#22 0x04161772 in QAbstractScrollArea::event(QEvent*) () from /usr/lib/libQtGui.so.4
#23 0x0430c297 in QGraphicsView::event(QEvent*) () from /usr/lib/libQtGui.so.4
#24 0x03cbeba4 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#25 0x03cc624b in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#26 0x047ad52b in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#27 0x036eccc3 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#28 0x03d13a6d in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#29 0x058be644 in Plasma::Dialog::event(QEvent*) () from /usr/lib/libplasma.so.3
#30 0x03cbeba4 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#31 0x03cc624b in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#32 0x047ad52b in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#33 0x036eccc3 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#34 0x03cc9a06 in QApplication::setActiveWindow(QWidget*) () from /usr/lib/libQtGui.so.4
#35 0x03d33587 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#36 0x03d5eea2 in ?? () from /usr/lib/libQtGui.so.4
#37 0x002bc118 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#38 0x002bfa48 in ?? () from /lib/libglib-2.0.so.0
#39 0x002bfb74 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#40 0x03717acd in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#41 0x03d5e566 in ?? () from /usr/lib/libQtGui.so.4
#42 0x036eb23a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#43 0x036eb69a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#44 0x036edb87 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#45 0x03cbea28 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#46 0x04fc660a in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#47 0x080486fc in _start ()

Reported using DrKonqi