Version:            (using KDE 4.2.4)
OS:                Linux
Installed from:    Ubuntu Packages

When clicking on "Lock Widgets" in the taskbarmenu, plasma crashed randomly. Never happened before though.
Here is the backtrace:

Anwendung: Plasma-Arbeitsfläche (plasma), Signal SIGSEGV
[Current thread is 0 (LWP 5495)]

Thread 3 (Thread 0xa931db90 (LWP 5500)):
#0  0xb7f17430 in __kernel_vsyscall ()
#1  0xb50870e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb626a2ed in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb64569b2 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#4  0xb78d5152 in ?? () from /usr/lib/libQtNetwork.so.4
#5  0xb645596e in ?? () from /usr/lib/libQtCore.so.4
#6  0xb50834ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb625b49e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 2 (Thread 0xa8af3b90 (LWP 5501)):
#0  0xb7f17430 in __kernel_vsyscall ()
#1  0xb50870e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb626a2ed in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb64569b2 in QWaitCondition::wait () from /usr/lib/libQtCore.so.4
#4  0xa9472b9a in ?? () from /usr/lib/kde4/plasma_wallpaper_image.so
#5  0xb645596e in ?? () from /usr/lib/libQtCore.so.4
#6  0xb50834ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb625b49e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb4b88710 (LWP 5495)):
[KCrash Handler]
#6  0xb6e24a9a in QGraphicsItem::isWidget () from /usr/lib/libQtGui.so.4
#7  0xb6e5ab27 in QGraphicsScene::event () from /usr/lib/libQtGui.so.4
#8  0xb67f6e9c in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#9  0xb67ff19e in QApplication::notify () from /usr/lib/libQtGui.so.4
#10 0xb764ce0d in KApplication::notify () from /usr/lib/libkdeui.so.5
#11 0xb6549a3b in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#12 0xb6e6b1c5 in QGraphicsView::viewportEvent () from /usr/lib/libQtGui.so.4
#13 0xb6cc9f55 in ?? () from /usr/lib/libQtGui.so.4
#14 0xb6548c5a in QCoreApplicationPrivate::sendThroughObjectEventFilters () from /usr/lib/libQtCore.so.4
#15 0xb67f6e7a in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#16 0xb67ff282 in QApplication::notify () from /usr/lib/libQtGui.so.4
#17 0xb764ce0d in KApplication::notify () from /usr/lib/libkdeui.so.5
#18 0xb6549a3b in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#19 0xb684d61d in QWidget::event () from /usr/lib/libQtGui.so.4
#20 0xb6c27993 in QFrame::event () from /usr/lib/libQtGui.so.4
#21 0xb6cc844d in QAbstractScrollArea::event () from /usr/lib/libQtGui.so.4
#22 0xb6e6aff6 in QGraphicsView::event () from /usr/lib/libQtGui.so.4
#23 0xb67f6e9c in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#24 0xb67ff282 in QApplication::notify () from /usr/lib/libQtGui.so.4
#25 0xb764ce0d in KApplication::notify () from /usr/lib/libkdeui.so.5
#26 0xb6549a3b in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#27 0xb67fdd9e in QApplication::setActiveWindow () from /usr/lib/libQtGui.so.4
#28 0xb686d56c in QApplication::x11ProcessEvent () from /usr/lib/libQtGui.so.4
#29 0xb6898c6a in ?? () from /usr/lib/libQtGui.so.4
#30 0xb4e81b88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#31 0xb4e850eb in ?? () from /usr/lib/libglib-2.0.so.0
#32 0xb4e85268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#33 0xb6575438 in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#34 0xb6898365 in ?? () from /usr/lib/libQtGui.so.4
#35 0xb654806a in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#36 0xb65484aa in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#37 0xb654a959 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#38 0xb67f6d17 in QApplication::exec () from /usr/lib/libQtGui.so.4
#39 0xb7ec1b56 in kdemain () from /usr/lib/libkdeinit4_plasma.so
#40 0x08048712 in _start ()