Version:            (using KDE 4.2.4)
Compiler:          gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4) 
OS:                Linux
Installed from:    Ubuntu Packages

Hello, here is what was open:

aMSN open
Firefox 3.0.10
rdesktop (open session)
mozilla thunderbird (email program)

Here is what i did:

When i opened a new tab in firefox it caused the plasma workspace to crash and cause a SIGSEGV. The icon bar of plasma disappear and reappear after a few seconds. Nothing is lost.

I enabled debugging. Let me know if you require more info:

Application: Plasma Workspace (plasma), signal SIGSEGV
[Current thread is 0 (LWP 3422)]

Thread 2 (Thread 0xa962ab90 (LWP 3423)):
#0  0xb80d5430 in __kernel_vsyscall ()
#1  0xb526f0e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb64272ed in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb66139b2 in QWaitCondition::wait (this=0x998b180, mutex=0x998b17c, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  0xa99cab9a in ?? () from /usr/lib/kde4/plasma_wallpaper_image.so
#5  0xb661296e in QThreadPrivate::start (arg=0x9940ac8) at thread/qthread_unix.cpp:189
#6  0xb526b4ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb641849e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb4d5c710 (LWP 3422)):
[KCrash Handler]
#6  0xb671d951 in QMetaObject::activate (sender=0xa5d3f70, m=0xa97a5bdc, local_signal_index=0, argv=0xbfef217c) at kernel/qobject.cpp:3139
#7  0xa977d0d3 in TaskManager::AbstractGroupingStrategy::groupRemoved () from /usr/lib/libtaskmanager.so.4
#8  0xa977e7d1 in TaskManager::AbstractGroupingStrategy::closeGroup () from /usr/lib/libtaskmanager.so.4
#9  0xa9785597 in ?? () from /usr/lib/libtaskmanager.so.4
#10 0xa978623b in ?? () from /usr/lib/libtaskmanager.so.4
#11 0xb671cca8 in QMetaObject::activate (sender=0x9f52208, from_signal_index=22, to_signal_index=22, argv=0xbfef231c) at kernel/qobject.cpp:3069
#12 0xb671d932 in QMetaObject::activate (sender=0x9f52208, m=0xa97a6b94, local_signal_index=1, argv=0xbfef231c) at kernel/qobject.cpp:3143
#13 0xa9797a63 in TaskManager::TaskGroup::itemRemoved () from /usr/lib/libtaskmanager.so.4
#14 0xa97980b0 in TaskManager::TaskGroup::remove () from /usr/lib/libtaskmanager.so.4
#15 0xa9780f10 in TaskManager::GroupManager::remove () from /usr/lib/libtaskmanager.so.4
#16 0xa9782c47 in TaskManager::GroupManager::qt_metacall () from /usr/lib/libtaskmanager.so.4
#17 0xb671cca8 in QMetaObject::activate (sender=0x9bd0ba0, from_signal_index=5, to_signal_index=5, argv=0xbfef248c) at kernel/qobject.cpp:3069
#18 0xb671d932 in QMetaObject::activate (sender=0x9bd0ba0, m=0xa97a6d5c, local_signal_index=1, argv=0xbfef248c) at kernel/qobject.cpp:3143
#19 0xa979b483 in TaskManager::TaskManager::taskRemoved () from /usr/lib/libtaskmanager.so.4
#20 0xa979cba9 in TaskManager::TaskManager::windowRemoved () from /usr/lib/libtaskmanager.so.4
#21 0xa979ea14 in TaskManager::TaskManager::qt_metacall () from /usr/lib/libtaskmanager.so.4
#22 0xb671cca8 in QMetaObject::activate (sender=0x98e3b28, from_signal_index=6, to_signal_index=6, argv=0xbfef25fc) at kernel/qobject.cpp:3069
#23 0xb671d932 in QMetaObject::activate (sender=0x98e3b28, m=0xb79b432c, local_signal_index=2, argv=0xbfef25fc) at kernel/qobject.cpp:3143
#24 0xb7953c03 in KWindowSystem::windowRemoved (this=0x98e3b28, _t1=54528353) at /build/buildd/kde4libs-4.2.4/obj-i486-linux-gnu/kdeui/kwindowsystem.moc:127
#25 0xb7956486 in KWindowSystemPrivate::removeClient (this=0x985bde8, w=54528353) at /build/buildd/kde4libs-4.2.4/kdeui/windowmanagement/kwindowsystem_x11.cpp:249
#26 0xb79659d2 in NETRootInfo::update (this=0x985bdfc, dirty_props=0xbfef2744) at /build/buildd/kde4libs-4.2.4/kdeui/windowmanagement/netwm.cpp:2125
#27 0xb7965d4f in NETRootInfo::event (this=0x985bdfc, event=0xbfef2e5c, properties=0xbfef2828, properties_size=5) at /build/buildd/kde4libs-4.2.4/kdeui/windowmanagement/netwm.cpp:2052
#28 0xb795671d in KWindowSystemPrivate::x11Event (this=0x985bde8, ev=0xbfef2dfc) at /build/buildd/kde4libs-4.2.4/kdeui/windowmanagement/kwindowsystem_x11.cpp:136
#29 0xb7809129 in KApplication::x11EventFilter (this=0x985f4b0, _event=0xbfef2dfc) at /build/buildd/kde4libs-4.2.4/kdeui/kernel/kapplication.cpp:946
#30 0xb8091517 in ?? () from /usr/lib/libkdeinit4_plasma.so
#31 0xb6a16f3e in qt_x11EventFilter (ev=0xbfef2dfc) at kernel/qapplication_x11.cpp:375
#32 0xb6a296a8 in QApplication::x11ProcessEvent (this=0x985f4b0, event=0xbfef2dfc) at kernel/qapplication_x11.cpp:3273
#33 0xb6a55c6a in x11EventSourceDispatch (s=0x98634e8, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#34 0xb5069b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0xb506d0eb in ?? () from /usr/lib/libglib-2.0.so.0
#36 0xb506d268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#37 0xb6732438 in QEventDispatcherGlib::processEvents (this=0x98242a0, flags={i = -1074843720}) at kernel/qeventdispatcher_glib.cpp:323
#38 0xb6a55365 in QGuiEventDispatcherGlib::processEvents (this=0x98242a0, flags={i = -1074843672}) at kernel/qguieventdispatcher_glib.cpp:202
#39 0xb670506a in QEventLoop::processEvents (this=0xbfef3060, flags={i = -1074843608}) at kernel/qeventloop.cpp:149
#40 0xb67054aa in QEventLoop::exec (this=0xbfef3060, flags={i = -1074843544}) at kernel/qeventloop.cpp:200
#41 0xb6707959 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:880
#42 0xb69b3d17 in QApplication::exec () at kernel/qapplication.cpp:3553
#43 0xb807eb56 in kdemain () from /usr/lib/libkdeinit4_plasma.so
#44 0x08048712 in _start ()