Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.1 (KDE 4.3.1)
Qt Version: 4.5.2
Operating System: Linux 2.6.28-15-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
I set the taskbar's grouping to, "Manually", created a group with alt+click, right-clicked and then clicked, "remove group". This resulted in the following crash.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 0 (LWP 4750)]

Thread 2 (Thread 0xa6841b90 (LWP 4752)):
#0  0xb800a430 in __kernel_vsyscall ()
#1  0xb651b0e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb66fb2ed in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb7e01172 in QWaitCondition::wait (this=0x938c368, mutex=0x938c364, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  0xb773eac2 in QHostInfoAgent::run (this=0x938c358) at kernel/qhostinfo.cpp:260
#5  0xb7e00132 in QThreadPrivate::start (arg=0x938c358) at thread/qthread_unix.cpp:188
#6  0xb65174ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb66ec49e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb6024a10 (LWP 4750)):
[KCrash Handler]
#6  TaskManager::TaskGroup::add (this=0x0, item=0x9433078) at /build/buildd/kdebase-workspace-4.3.1/libs/taskmanager/taskgroup.cpp:107
#7  0xa8676c06 in TaskManager::ManualGroupingStrategy::removeGroup (this=0x8dfdbe8) at /build/buildd/kdebase-workspace-4.3.1/libs/taskmanager/strategies/manualgroupingstrategy.cpp:118
#8  0xa867836b in TaskManager::ManualGroupingStrategy::qt_metacall (this=0x8dfdbe8, _c=QMetaObject::InvokeMetaMethod, _id=3, _a=0xbf92390c)
    at /build/buildd/kdebase-workspace-4.3.1/obj-i486-linux-gnu/libs/taskmanager/manualgroupingstrategy.moc:256
#9  0xb7f0a1b8 in QMetaObject::activate (sender=0xa881888, from_signal_index=5, to_signal_index=6, argv=0xbf92390c) at kernel/qobject.cpp:3113
#10 0xb7f0a5f0 in QMetaObject::activate (sender=0xa881888, m=0xb721ae48, from_local_signal_index=1, to_local_signal_index=2, argv=0xbf92390c) at kernel/qobject.cpp:3207
#11 0xb69ab6c1 in QAction::triggered (this=0xa881888, _t1=false) at .moc/release-shared/moc_qaction.cpp:236
#12 0xb69acc3f in QAction::activate (this=0xa881888, event=QAction::Trigger) at kernel/qaction.cpp:1160
#13 0xb6dfe0e4 in QMenuPrivate::activateCausedStack (this=0xa5db710, causedStack=@0xbf9239e8, action=0xa881888, action_e=QAction::Trigger, self=true) at widgets/qmenu.cpp:967
#14 0xb6e0483b in QMenuPrivate::activateAction (this=0xa5db710, action=0xa881888, action_e=QAction::Trigger, self=<value optimized out>) at widgets/qmenu.cpp:1060
#15 0xb6e05382 in QMenu::mouseReleaseEvent (this=0xbf9258f4, e=0xbf923f98) at widgets/qmenu.cpp:2254
#16 0xb6a08973 in QWidget::event (this=0xbf9258f4, event=0xbf923f98) at kernel/qwidget.cpp:7549
#17 0xb6e07639 in QMenu::event (this=0xbf9258f4, e=0xbf923f98) at widgets/qmenu.cpp:2353
#18 0xb69b1d3c in QApplicationPrivate::notify_helper (this=0x8657df8, receiver=0xbf9258f4, e=0xbf923f98) at kernel/qapplication.cpp:4056
#19 0xb69ba9b1 in QApplication::notify (this=0x8652260, receiver=0xbf9258f4, e=0xbf923f98) at kernel/qapplication.cpp:3758
#20 0xb74c285d in KApplication::notify (this=0x8652260, receiver=0xbf9258f4, event=0xbf923f98) at /build/buildd/kde4libs-4.3.1/kdeui/kernel/kapplication.cpp:302
#21 0xb7ef4bcb in QCoreApplication::notifyInternal (this=0x8652260, receiver=0xbf9258f4, event=0xbf923f98) at kernel/qcoreapplication.cpp:610
#22 0xb69b9a1e in QApplicationPrivate::sendMouseEvent (receiver=0xbf9258f4, event=0xbf923f98, alienWidget=0x0, nativeWidget=0xbf9258f4, buttonDown=0xb7233aa0, lastMouseReceiver=@0xb7233aa4)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#23 0xb6a29f56 in QETWidget::translateMouseEvent (this=0xbf9258f4, event=0xbf92562c) at kernel/qapplication_x11.cpp:4343
#24 0xb6a29085 in QApplication::x11ProcessEvent (this=0x8652260, event=0xbf92562c) at kernel/qapplication_x11.cpp:3428
#25 0xb6a5437a in x11EventSourceDispatch (s=0x865ac68, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#26 0xb6564b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#27 0xb65680eb in ?? () from /usr/lib/libglib-2.0.so.0
#28 0xb6568268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#29 0xb7f202f8 in QEventDispatcherGlib::processEvents (this=0x86578c8, flags={i = -1080928280}) at kernel/qeventdispatcher_glib.cpp:327
#30 0xb6a53a75 in QGuiEventDispatcherGlib::processEvents (this=0x86578c8, flags={i = -1080928232}) at kernel/qguieventdispatcher_glib.cpp:202
#31 0xb7ef31fa in QEventLoop::processEvents (this=0xbf92588c, flags={i = -1080928168}) at kernel/qeventloop.cpp:149
#32 0xb7ef3642 in QEventLoop::exec (this=0xbf92588c, flags={i = -1080928108}) at kernel/qeventloop.cpp:201
#33 0xb6e074a1 in QMenu::exec (this=0xbf9258f4, p=@0xbf92591c, action=0x0) at widgets/qmenu.cpp:1993
#34 0xa86d6438 in TaskGroupItem::contextMenuEvent (this=0x88a9958, e=0xbf925e8c) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskgroupitem.cpp:407
#35 0xb6fbf118 in QGraphicsItem::sceneEvent (this=0x88a9960, event=0xbf925e8c) at graphicsview/qgraphicsitem.cpp:5000
#36 0xb700f95f in QGraphicsWidget::sceneEvent (this=0x88a9958, event=0xbf925e8c) at graphicsview/qgraphicswidget.cpp:1110
#37 0xb6fe47bc in QGraphicsScenePrivate::sendEvent (this=0x86f3618, item=0x88a9960, event=0xbf925e8c) at graphicsview/qgraphicsscene.cpp:1159
#38 0xb6ff109f in QGraphicsScene::contextMenuEvent (this=0x869ec38, contextMenuEvent=0xbf925e8c) at graphicsview/qgraphicsscene.cpp:3956
#39 0xb6ff204a in QGraphicsScene::event (this=0x869ec38, event=0xbf925e8c) at graphicsview/qgraphicsscene.cpp:3766
#40 0xb69b1d3c in QApplicationPrivate::notify_helper (this=0x8657df8, receiver=0x869ec38, e=0xbf925e8c) at kernel/qapplication.cpp:4056
#41 0xb69ba03e in QApplication::notify (this=0x8652260, receiver=0x869ec38, e=0xbf925e8c) at kernel/qapplication.cpp:3603
#42 0xb74c285d in KApplication::notify (this=0x8652260, receiver=0x869ec38, event=0xbf925e8c) at /build/buildd/kde4libs-4.3.1/kdeui/kernel/kapplication.cpp:302
#43 0xb7ef4bcb in QCoreApplication::notifyInternal (this=0x8652260, receiver=0x869ec38, event=0xbf925e8c) at kernel/qcoreapplication.cpp:610
#44 0xb6fff0a6 in QGraphicsView::contextMenuEvent (this=0x98e1a08, event=0xbf926480) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#45 0xb6a0905c in QWidget::event (this=0x98e1a08, event=0xbf926480) at kernel/qwidget.cpp:7708
#46 0xb6db9a53 in QFrame::event (this=0x98e1a08, e=0xbf926480) at widgets/qframe.cpp:559
#47 0xb6e59c2f in QAbstractScrollArea::viewportEvent (this=0x98e1a08, e=0x0) at widgets/qabstractscrollarea.cpp:962
#48 0xb70049b2 in QGraphicsView::viewportEvent (this=0x98e1a08, event=0xbf926480) at graphicsview/qgraphicsview.cpp:2919
#49 0xb6e5c235 in QAbstractScrollAreaFilter::eventFilter (this=0x89b5ef0, o=0x9d42c70, e=0xbf926480) at widgets/qabstractscrollarea_p.h:100
#50 0xb7ef3dea in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x8657df8, receiver=0x9d42c70, event=0xbf926480) at kernel/qcoreapplication.cpp:726
#51 0xb69b1d1a in QApplicationPrivate::notify_helper (this=0x8657df8, receiver=0x9d42c70, e=0xbf926480) at kernel/qapplication.cpp:4052
#52 0xb69ba57d in QApplication::notify (this=0x8652260, receiver=0x9d42c70, e=0xbf926480) at kernel/qapplication.cpp:3845
#53 0xb74c285d in KApplication::notify (this=0x8652260, receiver=0x9d42c70, event=0xbf926480) at /build/buildd/kde4libs-4.3.1/kdeui/kernel/kapplication.cpp:302
#54 0xb7ef4bcb in QCoreApplication::notifyInternal (this=0x8652260, receiver=0x9d42c70, event=0xbf926480) at kernel/qcoreapplication.cpp:610
#55 0xb69bce8e in QCoreApplication::sendSpontaneousEvent (receiver=0x9d42c70, event=0x0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#56 0xb6a2a4b7 in QETWidget::translateMouseEvent (this=0x98e1a08, event=0xbf927aec) at kernel/qapplication_x11.cpp:4415
#57 0xb6a29085 in QApplication::x11ProcessEvent (this=0x8652260, event=0xbf927aec) at kernel/qapplication_x11.cpp:3428
#58 0xb6a5437a in x11EventSourceDispatch (s=0x865ac68, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#59 0xb6564b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#60 0xb65680eb in ?? () from /usr/lib/libglib-2.0.so.0
#61 0xb6568268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#62 0xb7f202f8 in QEventDispatcherGlib::processEvents (this=0x86578c8, flags={i = -1080918872}) at kernel/qeventdispatcher_glib.cpp:327
#63 0xb6a53a75 in QGuiEventDispatcherGlib::processEvents (this=0x86578c8, flags={i = -1080918824}) at kernel/qguieventdispatcher_glib.cpp:202
#64 0xb7ef31fa in QEventLoop::processEvents (this=0xbf927d50, flags={i = -1080918760}) at kernel/qeventloop.cpp:149
#65 0xb7ef3642 in QEventLoop::exec (this=0xbf927d50, flags={i = -1080918696}) at kernel/qeventloop.cpp:201
#66 0xb7ef5ae9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#67 0xb69b1bb7 in QApplication::exec () at kernel/qapplication.cpp:3525
#68 0xb3c11310 in kdemain (argc=1, argv=0x861f948) at /build/buildd/kdebase-workspace-4.3.1/plasma/shells/desktop/main.cpp:50
#69 0x0804e27d in launch (argc=1, _name=0x863f31c "/usr/bin/plasma-desktop", args=0x863f334 "", cwd=0x0, envc=0, envs=0x863f338 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x805136d "0") at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:677
#70 0x0804ea5d in handle_launcher_request (sock=7, who=<value optimized out>) at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:1169
#71 0x0804efe5 in handle_requests (waitForPid=0) at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:1362
#72 0x0804fbca in main (argc=2, argv=0xbf928544, envp=0xbf928550) at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:1793

Reported using DrKonqi