Application: plasma-desktop (0.3)
KDE Version: 4.3.74 (KDE 4.3.74 (KDE 4.4 >= 20091102)) (Compiled from sources)
Qt Version: 4.6.0
Operating System: Linux 2.6.31-trunk-amd64 x86_64
Distribution: Debian GNU/Linux testing (squeeze)

What I was doing when the application crashed:
Plasma desktop crashed after click Don't allow this program to be grouped

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0x7fc29ada47f0 (LWP 3706))]

Thread 2 (Thread 0x7fc273013910 (LWP 3996)):
#0  0x00007fc29a62ff99 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007fc29a8ca659 in QWaitConditionPrivate::wait (this=0x2a1d5d0, mutex=0x2a1d5c8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x2a1d5d0, mutex=0x2a1d5c8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007fc299497994 in QHostInfoAgent::run (this=0x2a1d5b0) at kernel/qhostinfo.cpp:252
#4  0x00007fc29a8c9765 in QThreadPrivate::start (arg=0x2a1d5b0) at thread/qthread_unix.cpp:244
#5  0x00007fc29a62b73a in start_thread () from /lib/libpthread.so.0
#6  0x00007fc296fab2fd in clone () from /lib/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fc29ada47f0 (LWP 3706)):
[KCrash Handler]
#5  QGraphicsScenePrivate::processDirtyItemsRecursive (this=0x1e3a680, item=0x3211050, dirtyAncestorContainsChildren=false, parentOpacity=8.256666972292243e-317)
    at graphicsview/qgraphicsscene.cpp:4825
#6  0x00007fc2981ec1b7 in QGraphicsScenePrivate::_q_processDirtyItems (this=0x1e3a680) at graphicsview/qgraphicsscene.cpp:465
#7  0x00007fc2981ec72a in QGraphicsScene::qt_metacall (this=0x1e3a4e0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x2e29ef0) at .moc/release-shared/moc_qgraphicsscene.cpp:128
#8  0x00007fc28bbadbf5 in Plasma::Corona::qt_metacall(QMetaObject::Call, int, void**) () from /opt/kde4/lib/libplasma.so.3
#9  0x00007fc2873407e5 in DesktopCorona::qt_metacall(QMetaObject::Call, int, void**) () from /opt/kde4/lib/libkdeinit4_plasma-desktop.so
#10 0x00007fc29a9cd438 in QObject::event (this=0x1e3a4e0, e=0x2e11e90) at kernel/qobject.cpp:1246
#11 0x00007fc2981e75a2 in QGraphicsScene::event (this=0x1e3a4e0, event=0x2e11e90) at graphicsview/qgraphicsscene.cpp:3388
#12 0x00007fc297bd1b1d in QApplicationPrivate::notify_helper (this=0x1df04d0, receiver=0x1e3a4e0, e=0x2e11e90) at kernel/qapplication.cpp:4245
#13 0x00007fc297bd8fa0 in QApplication::notify (this=0x1dd8b90, receiver=0x1e3a4e0, e=0x2e11e90) at kernel/qapplication.cpp:4133
#14 0x00007fc298db1a6b in KApplication::notify(QObject*, QEvent*) () from /opt/kde4/lib/libkdeui.so.5
#15 0x00007fc29a9bd35c in QCoreApplication::notifyInternal (this=0x1dd8b90, receiver=0x1e3a4e0, event=0x2e11e90) at kernel/qcoreapplication.cpp:704
#16 0x00007fc29a9be23c in QCoreApplication::sendEvent (receiver=0x0, event_type=0, data=0x1d6c300) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#17 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x1d6c300) at kernel/qcoreapplication.cpp:1345
#18 0x00007fc29a9e7213 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#19 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:276
#20 0x00007fc29642f12a in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#21 0x00007fc296432988 in ?? () from /lib/libglib-2.0.so.0
#22 0x00007fc296432b3c in g_main_context_iteration () from /lib/libglib-2.0.so.0
#23 0x00007fc29a9e6d7c in QEventDispatcherGlib::processEvents (this=0x1deffd0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:407
#24 0x00007fc297c7b75f in QGuiEventDispatcherGlib::processEvents (this=0x1e3a680, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#25 0x00007fc29a9bbc62 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#26 0x00007fc29a9bc034 in QEventLoop::exec (this=0x7fff7e27c7b0, flags=...) at kernel/qeventloop.cpp:201
#27 0x00007fc29a9be4c6 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#28 0x00007fc287347bda in kdemain () from /opt/kde4/lib/libkdeinit4_plasma-desktop.so
#29 0x00000000004074b4 in launch(int, char const*, char const*, char const*, int, char const*, bool, char const*, bool, char const*) ()
#30 0x0000000000407c78 in handle_launcher_request(int, char const*) ()
#31 0x0000000000408111 in handle_requests(int) ()
#32 0x00000000004088cb in main ()

Reported using DrKonqi