Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.2.95 (KDE 4.2.95 (KDE 4.3 RC1))
Qt Version: 4.5.2
Operating System: Linux 2.6.30-ARCH x86_64

What I was doing when the application crashed:
kde version : 4.3 rc2 (4.2.95)
qt version : 4.5.2 & kde-qt patches
distribution : archlinux 64

After upgrading to 4.2.95(snapshot created 25-26/06/09) i get this crash very often. There is no main reason. Sometimes it happens when i click my mouse on the task manager, sometimes it happens when i don't do anything. 

I tried removing some of my extra plasmoids (stdin, quickaccess, magic folder, etc) but the crash still remains.

I have to mention but after this type of crash, plasma-desktop restarts automatically, but with the extra option --nocrashhandler.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 0 (LWP 31692)]

Thread 2 (Thread 0x7fcf9a9ba910 (LWP 31701)):
#0  0x00007fcfbd3e6e99 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007fcfbd65733b in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#2  0x00007fcfb9acc34c in ?? () from /usr/lib/libQtNetwork.so.4
#3  0x00007fcfbd656285 in ?? () from /usr/lib/libQtCore.so.4
#4  0x00007fcfbd3e259a in start_thread () from /lib/libpthread.so.0
#5  0x00007fcfbada9c3d in clone () from /lib/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fcfbdc14760 (LWP 31692)):
[KCrash Handler]
#5  0x00007fcfa1440396 in TaskManager::GroupManager::manualSortingRequest () from /usr/lib/libtaskmanager.so.4
#6  0x00007fcfa143e7d7 in TaskManager::AbstractGroupingStrategy::closeGroup () from /usr/lib/libtaskmanager.so.4
#7  0x00007fcfa144569b in TaskManager::ProgramGroupingStrategy::checkGroup () from /usr/lib/libtaskmanager.so.4
#8  0x00007fcfa14462a5 in TaskManager::ProgramGroupingStrategy::qt_metacall () from /usr/lib/libtaskmanager.so.4
#9  0x00007fcfbd750a8c in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#10 0x00007fcfa1456e72 in TaskManager::TaskGroup::itemRemoved () from /usr/lib/libtaskmanager.so.4
#11 0x00007fcfa1457541 in TaskManager::TaskGroup::remove () from /usr/lib/libtaskmanager.so.4
#12 0x00007fcfa1440da8 in TaskManager::GroupManagerPrivate::removeTask () from /usr/lib/libtaskmanager.so.4
#13 0x00007fcfa1441793 in TaskManager::GroupManagerPrivate::actuallyReloadTasks () from /usr/lib/libtaskmanager.so.4
#14 0x00007fcfa1443049 in TaskManager::GroupManager::qt_metacall () from /usr/lib/libtaskmanager.so.4
#15 0x00007fcfbd750a8c in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#16 0x00007fcfbd74aa43 in QObject::event () from /usr/lib/libQtCore.so.4
#17 0x00007fcfbb4dfe1c in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#18 0x00007fcfbb4e70ee in QApplication::notify () from /usr/lib/libQtGui.so.4
#19 0x00007fcfbc10ece6 in KApplication::notify () from /usr/lib/libkdeui.so.5
#20 0x00007fcfbd73b9bc in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#21 0x00007fcfbd767012 in ?? () from /usr/lib/libQtCore.so.4
#22 0x00007fcfbd763f7d in ?? () from /usr/lib/libQtCore.so.4
#23 0x00007fcfba432dee in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#24 0x00007fcfba4364b8 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#25 0x00007fcfba4365e0 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#26 0x00007fcfbd763ec6 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#27 0x00007fcfbb572d4e in ?? () from /usr/lib/libQtGui.so.4
#28 0x00007fcfbd73a2c2 in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#29 0x00007fcfbd73a694 in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#30 0x00007fcfbd73c849 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#31 0x00007fcfb15b6fdf in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#32 0x0000000000406e0e in _start ()

Reported using DrKonqi