Version:            (using Devel)
Installed from:    Compiled sources
Compiler:          gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7) 
OS:                Linux

Plasma crashes at random when locking widgets, I can't reproduce it consistently as it happens at random.

Version 4.00.98 (KDE 4.0.98 (4.1 RC1)

Backtrace.

Application: Plasma Workspace (plasma), signal SIGSEGV
[Thread debugging using libthread_db enabled]
[New Thread 0xb46eb740 (LWP 5721)]
[New Thread 0xae171b90 (LWP 5990)]
[New Thread 0xaf0e6b90 (LWP 5989)]
[New Thread 0xaf8e7b90 (LWP 5988)]
[New Thread 0xb00e8b90 (LWP 5987)]
[New Thread 0xb08e9b90 (LWP 5986)]
[New Thread 0xb10eab90 (LWP 5985)]
[New Thread 0xb18ebb90 (LWP 5724)]
[New Thread 0xb2ad5b90 (LWP 5723)]
[KCrash handler]
#6  0xb6992168 in QCoreApplication::postEvent () from /usr/lib/libQtCore.so.4
#7  0xb699243c in QCoreApplication::postEvent () from /usr/lib/libQtCore.so.4
#8  0xb69a0377 in QObject::deleteLater () from /usr/lib/libQtCore.so.4
#9  0xb7e2fcd0 in Plasma::ContainmentPrivate::toggleDesktopImmutability ()
   from /usr/lib/kde4/lib/libplasma.so.2
#10 0xb7e306f3 in Plasma::Containment::qt_metacall ()
   from /usr/lib/kde4/lib/libplasma.so.2
#11 0xb2ccc08a in DefaultDesktop::qt_metacall ()
   from /usr/lib/kde4/lib/kde4/plasma_containment_desktop.so
#12 0xb69a64f9 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#13 0xb69a6930 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#14 0xb5d0edd1 in QAction::triggered () from /usr/lib/libQtGui.so.4
#15 0xb5d0f79f in QAction::activate () from /usr/lib/libQtGui.so.4
#16 0xb60eaed1 in ?? () from /usr/lib/libQtGui.so.4
#17 0xb60ed734 in QMenu::mouseReleaseEvent () from /usr/lib/libQtGui.so.4
#18 0xb7a0d69f in KMenu::mouseReleaseEvent ()
   from /usr/lib/kde4/lib/libkdeui.so.5
#19 0xb5d6d4a4 in QWidget::event () from /usr/lib/libQtGui.so.4
#20 0xb60e8845 in QMenu::event () from /usr/lib/libQtGui.so.4
#21 0xb5d15c0c in QApplicationPrivate::notify_helper ()
   from /usr/lib/libQtGui.so.4
#22 0xb5d1acd5 in QApplication::notify () from /usr/lib/libQtGui.so.4
#23 0xb794742d in KApplication::notify () from /usr/lib/kde4/lib/libkdeui.so.5
#24 0xb69916a9 in QCoreApplication::notifyInternal ()
   from /usr/lib/libQtCore.so.4
#25 0xb5d17e21 in QApplicationPrivate::sendMouseEvent ()
   from /usr/lib/libQtGui.so.4
#26 0xb5d81f0c in ?? () from /usr/lib/libQtGui.so.4
#27 0xb5d806b1 in QApplication::x11ProcessEvent () from /usr/lib/libQtGui.so.4
#28 0xb5da93ba in ?? () from /usr/lib/libQtGui.so.4
#29 0xb5618bf8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#30 0xb561be5e in ?? () from /usr/lib/libglib-2.0.so.0
#31 0xb561c3ac in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#32 0xb69bcf98 in QEventDispatcherGlib::processEvents ()
   from /usr/lib/libQtCore.so.4
#33 0xb5da91b5 in ?? () from /usr/lib/libQtGui.so.4
#34 0xb699092d in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#35 0xb6990abd in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#36 0xb60ed9b7 in QMenu::exec () from /usr/lib/libQtGui.so.4
#37 0xb7e3315c in Plasma::Containment::contextMenuEvent ()
   from /usr/lib/kde4/lib/libplasma.so.2
#38 0xb6285049 in QGraphicsItem::sceneEvent () from /usr/lib/libQtGui.so.4
#39 0xb62c732c in QGraphicsWidget::sceneEvent () from /usr/lib/libQtGui.so.4
#40 0xb629e3cc in ?? () from /usr/lib/libQtGui.so.4
#41 0xb62aa7e5 in QGraphicsScene::contextMenuEvent ()
   from /usr/lib/libQtGui.so.4
#42 0xb62ab5c6 in QGraphicsScene::event () from /usr/lib/libQtGui.so.4
#43 0xb5d15c0c in QApplicationPrivate::notify_helper ()
   from /usr/lib/libQtGui.so.4
#44 0xb5d1a7a9 in QApplication::notify () from /usr/lib/libQtGui.so.4
#45 0xb794742d in KApplication::notify () from /usr/lib/kde4/lib/libkdeui.so.5
#46 0xb69916a9 in QCoreApplication::notifyInternal ()
   from /usr/lib/libQtCore.so.4
#47 0xb62bb710 in QGraphicsView::contextMenuEvent ()
   from /usr/lib/libQtGui.so.4
#48 0xb5d6d9b0 in QWidget::event () from /usr/lib/libQtGui.so.4
#49 0xb60a2063 in QFrame::event () from /usr/lib/libQtGui.so.4
#50 0xb6135c0f in QAbstractScrollArea::viewportEvent ()
   from /usr/lib/libQtGui.so.4
#51 0xb62bb7cf in QGraphicsView::viewportEvent () from /usr/lib/libQtGui.so.4
#52 0xb6136f95 in ?? () from /usr/lib/libQtGui.so.4
#53 0xb6991a21 in QCoreApplicationPrivate::sendThroughObjectEventFilters ()
   from /usr/lib/libQtCore.so.4
#54 0xb5d15be3 in QApplicationPrivate::notify_helper ()
   from /usr/lib/libQtGui.so.4
#55 0xb5d1b00e in QApplication::notify () from /usr/lib/libQtGui.so.4
#56 0xb794742d in KApplication::notify () from /usr/lib/kde4/lib/libkdeui.so.5
#57 0xb69916a9 in QCoreApplication::notifyInternal ()
   from /usr/lib/libQtCore.so.4
#58 0xb5d82448 in ?? () from /usr/lib/libQtGui.so.4
#59 0xb5d806b1 in QApplication::x11ProcessEvent () from /usr/lib/libQtGui.so.4
#60 0xb5da93ba in ?? () from /usr/lib/libQtGui.so.4
#61 0xb5618bf8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#62 0xb561be5e in ?? () from /usr/lib/libglib-2.0.so.0
#63 0xb561c3ac in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#64 0xb69bcf98 in QEventDispatcherGlib::processEvents ()
   from /usr/lib/libQtCore.so.4
#65 0xb5da91b5 in ?? () from /usr/lib/libQtGui.so.4
#66 0xb699092d in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#67 0xb6990abd in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#68 0xb6992d3d in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#69 0xb5d15567 in QApplication::exec () from /usr/lib/libQtGui.so.4
#70 0xb7f24b56 in kdemain () from /usr/lib/kde4/lib/libkdeinit4_plasma.so
#71 0x080487d2 in main ()
#0  0xb7f3d410 in __kernel_vsyscall ()