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: 4.5.0
Operating System: Linux 2.6.28-13-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
OS: Kubuntu Jaunty 9.04 (KDE 4.2.95)
Plasma-desktop crashes randomly when I am trying to close/hide applications. More often it crashes after kopete chat window closed. Also (sometimes) plasma-desktop crashes after Firefox, Amarok, Thunderbird window closing.

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 0 (LWP 6309)]

Thread 2 (Thread 0xa8b23b90 (LWP 6310)):
#0  0xb8023430 in __kernel_vsyscall ()
#1  0xb50fa0e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb63222ed in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb650e9b2 in QWaitCondition::wait (this=0x8eab1d8, mutex=0x8eab1d4, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  0xb7996152 in QHostInfoAgent::run (this=0x8eab1c8) at kernel/qhostinfo.cpp:260
#5  0xb650d96e in QThreadPrivate::start (arg=0x8eab1c8) at thread/qthread_unix.cpp:189
#6  0xb50f64ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb631349e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb43b8b70 (LWP 6309)):
[KCrash Handler]
#6  0xa8d1c32a in TaskManager::GroupManager::manualSortingRequest () from /usr/lib/libtaskmanager.so.4
#7  0xa8d1a31b in TaskManager::AbstractGroupingStrategy::closeGroup () from /usr/lib/libtaskmanager.so.4
#8  0xa8d21f27 in ?? () from /usr/lib/libtaskmanager.so.4
#9  0xa8d22e5b in ?? () from /usr/lib/libtaskmanager.so.4
#10 0xb6617ca8 in QMetaObject::activate (sender=0x8d92370, from_signal_index=22, to_signal_index=22, argv=0xbf93fb6c) at kernel/qobject.cpp:3069
#11 0xb6618932 in QMetaObject::activate (sender=0x8d92370, m=0xa8d44b74, local_signal_index=1, argv=0xbf93fb6c) at kernel/qobject.cpp:3143
#12 0xa8d35d83 in TaskManager::TaskGroup::itemRemoved () from /usr/lib/libtaskmanager.so.4
#13 0xa8d367ab in TaskManager::TaskGroup::remove () from /usr/lib/libtaskmanager.so.4
#14 0xa8d369a6 in TaskManager::TaskGroup::add () from /usr/lib/libtaskmanager.so.4
#15 0xa8d1cd0a in ?? () from /usr/lib/libtaskmanager.so.4
#16 0xa8d1d32a in ?? () from /usr/lib/libtaskmanager.so.4
#17 0xa8d1f3ce in TaskManager::GroupManager::qt_metacall () from /usr/lib/libtaskmanager.so.4
#18 0xb6617ca8 in QMetaObject::activate (sender=0x8d67720, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3069
#19 0xb6618932 in QMetaObject::activate (sender=0x8d67720, m=0xb66f4904, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3143
#20 0xb6653717 in QTimer::timeout (this=0x8d67720) at .moc/release-shared/moc_qtimer.cpp:128
#21 0xb661d6fe in QTimer::timerEvent (this=0x8d67720, e=0xbf94022c) at kernel/qtimer.cpp:261
#22 0xb661215f in QObject::event (this=0x8d67720, e=0xbf94022c) at kernel/qobject.cpp:1082
#23 0xb68aee9c in QApplicationPrivate::notify_helper (this=0x8785d48, receiver=0x8d67720, e=0xbf94022c) at kernel/qapplication.cpp:4084
#24 0xb68b719e in QApplication::notify (this=0x87795f0, receiver=0x8d67720, e=0xbf94022c) at kernel/qapplication.cpp:3631
#25 0xb77173dd in KApplication::notify (this=0x87795f0, receiver=0x8d67720, event=0xbf94022c) at /build/buildd/kde4libs-4.2.95/kdeui/kernel/kapplication.cpp:302
#26 0xb6601a3b in QCoreApplication::notifyInternal (this=0x87795f0, receiver=0x8d67720, event=0xbf94022c) at kernel/qcoreapplication.cpp:602
#27 0xb6630d71 in QTimerInfoList::activateTimers (this=0x878a87c) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#28 0xb662d4e0 in timerSourceDispatch (source=0x878a848) at kernel/qeventdispatcher_glib.cpp:164
#29 0xb4ef4b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#30 0xb4ef80eb in ?? () from /usr/lib/libglib-2.0.so.0
#31 0xb4ef8268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#32 0xb662d438 in QEventDispatcherGlib::processEvents (this=0x877d570, flags={i = -1080818776}) at kernel/qeventdispatcher_glib.cpp:323
#33 0xb6950365 in QGuiEventDispatcherGlib::processEvents (this=0x877d570, flags={i = -1080818728}) at kernel/qguieventdispatcher_glib.cpp:202
#34 0xb660006a in QEventLoop::processEvents (this=0xbf940450, flags={i = -1080818664}) at kernel/qeventloop.cpp:149
#35 0xb66004aa in QEventLoop::exec (this=0xbf940450, flags={i = -1080818600}) at kernel/qeventloop.cpp:200
#36 0xb6602959 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:880
#37 0xb68aed17 in QApplication::exec () at kernel/qapplication.cpp:3553
#38 0xb7fc2510 in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#39 0x08048712 in _start ()

Reported using DrKonqi