Application: plasma-desktop (0.3)
KDE Platform Version: 4.4.5 (KDE 4.4.5)
Qt Version: 4.6.3
Operating System: Linux 2.6.34-1-amd64 x86_64
Distribution: Debian GNU/Linux 5.0.5 (lenny)

-- Information about the crash:
Very short after the Thunderbird mail window closes on sending a message, Plasma may crash. This is repeatable once in a few e-mail sends. Nothing else very special.

The crash can be reproduced some of the time.

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[KCrash Handler]
#5  0x0000036c00000000 in ?? ()
#6  0x00007f5b8d0e922b in KSharedPtr<TaskManager::Task>::attach (this=0x1f179e0) at /usr/include/ksharedptr.h:214
#7  KSharedPtr<TaskManager::Task>::operator= (this=0x1f179e0) at /usr/include/ksharedptr.h:97
#8  KWinButtonApplet::findActiveTask (this=0x1f179e0) at /home/alex/programs/kwinbuttonapplet-0.1/applet.cpp:154
#9  0x00007f5b8d0e9418 in KWinButtonApplet::windowChanged (this=0x1f179e0, task=) at /home/alex/programs/kwinbuttonapplet-0.1/applet.cpp:144
#10 0x00007f5b8d0e9d2a in KWinButtonApplet::qt_metacall (this=0x1f179e0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffbe3fabd0)
    at /home/alex/programs/kwinbuttonapplet-0.1/build/applet.moc:82
#11 0x00007f5baa9fa346 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#12 0x00007f5b8ced0bda in TaskManager::TaskManager::windowChanged(KSharedPtr<TaskManager::Task>, QFlags<TaskManager::TaskChange>) () from /usr/lib/libtaskmanager.so.4
#13 0x00007f5b8ced3d35 in TaskManager::TaskManager::taskChanged(QFlags<TaskManager::TaskChange>) () from /usr/lib/libtaskmanager.so.4
#14 0x00007f5b8ced4187 in TaskManager::TaskManager::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libtaskmanager.so.4
#15 0x00007f5baa9fa346 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#16 0x00007f5b8cec2472 in TaskManager::Task::changed(QFlags<TaskManager::TaskChange>) () from /usr/lib/libtaskmanager.so.4
#17 0x00007f5b8cec24a9 in TaskManager::Task::setActive(bool) () from /usr/lib/libtaskmanager.so.4
#18 0x00007f5b8ced1935 in TaskManager::TaskManager::activeWindowChanged(unsigned long) () from /usr/lib/libtaskmanager.so.4
#19 0x00007f5b8ced40cf in TaskManager::TaskManager::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libtaskmanager.so.4
#20 0x00007f5baa9fa346 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#21 0x00007f5bac4611e2 in KWindowSystem::activeWindowChanged(unsigned long) () from /usr/lib/libkdeui.so.5
#22 0x00007f5bac464406 in ?? () from /usr/lib/libkdeui.so.5
#23 0x00007f5bac328d06 in KApplication::x11EventFilter(_XEvent*) () from /usr/lib/libkdeui.so.5
#24 0x00007f5bae4b57f4 in ?? () from /usr/lib/kde4/libkdeinit/libkdeinit4_plasma-desktop.so
#25 0x00007f5bab1e77a1 in ?? () from /usr/lib/libQtGui.so.4
#26 0x00007f5bab1f62b1 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#27 0x00007f5bab222552 in ?? () from /usr/lib/libQtGui.so.4
#28 0x00007f5ba41df6c2 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#29 0x00007f5ba41e3538 in ?? () from /lib/libglib-2.0.so.0
#30 0x00007f5ba41e36ec in g_main_context_iteration () from /lib/libglib-2.0.so.0
#31 0x00007f5baaa10713 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#32 0x00007f5bab22214e in ?? () from /usr/lib/libQtGui.so.4
#33 0x00007f5baa9e5a82 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#34 0x00007f5baa9e5e5c in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#35 0x00007f5baa9eaaeb in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#36 0x00007f5bae4a3eb2 in kdemain () from /usr/lib/kde4/libkdeinit/libkdeinit4_plasma-desktop.so
#37 0x00007f5bae125c4d in __libc_start_main (main=<value optimized out>, argc=<value optimized out>, ubp_av=<value optimized out>, init=<value optimized out>, fini=<value optimized out>, 
    rtld_fini=<value optimized out>, stack_end=0x7fffbe3fbed8) at libc-start.c:228
#38 0x0000000000400689 in _start ()

Reported using DrKonqi