Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.4 (KDE 4.3.4)
Qt Version: 4.5.3
Operating System: Linux 2.6.32-trunk-686 i686
Distribution: Debian GNU/Linux unstable (sid)

What I was doing when the application crashed:
preamble:
often in my system, when i open an application, two buttons for the same application are shown in the taskbar.
both buttons are for the same instance of the application.
when i close the application usually one of the buttons disappears while the other remains there until i logout.
this is very annoying.

this time i launched icedove (debian thunderbird) and it showed as 2 buttons.
when i closed it i had the crash.

the multiple button problem is not strictly related to the icedove application. it happens with all the applications.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0xb5799700 (LWP 2176))]

Thread 2 (Thread 0xa71ffb70 (LWP 2180)):
#0  0xb77d8424 in __kernel_vsyscall ()
#1  0xb5eef0a5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i686/cmov/libpthread.so.0
#2  0xb60b17dd in pthread_cond_wait () from /lib/i686/cmov/libc.so.6
#3  0xb75f15c2 in QWaitConditionPrivate::wait (this=0xa2fd080, mutex=0xa2fd07c, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  QWaitCondition::wait (this=0xa2fd080, mutex=0xa2fd07c, time=4294967295) at thread/qwaitcondition_unix.cpp:159
#5  0xb5e02a9a in QHostInfoAgent::run (this=0xa2fd070) at kernel/qhostinfo.cpp:260
#6  0xb75f05e2 in QThreadPrivate::start (arg=0xa2fd070) at thread/qthread_unix.cpp:188
#7  0xb5eeb585 in start_thread () from /lib/i686/cmov/libpthread.so.0
#8  0xb60a426e in clone () from /lib/i686/cmov/libc.so.6

Thread 1 (Thread 0xb5799700 (LWP 2176)):
[KCrash Handler]
#6  Tasks::itemTopMargin (this=0xa7a8e98) at ../../../../plasma/applets/tasks/tasks.h:92
#7  AbstractTaskItem::basicPreferredSize (this=0xa7a8e98) at ../../../../plasma/applets/tasks/abstracttaskitem.cpp:100
#8  0xa800065b in TaskItemLayout::preferredColumns (this=0xa34e910) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:211
#9  0xa800145a in TaskItemLayout::gridLayoutSize (this=0xa34e910) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:227
#10 0xa800151c in TaskItemLayout::layoutItems (this=0xa34e910) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:250
#11 0xa800273a in TaskItemLayout::remove (this=0xa34e910, item=0xaa3db98) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:141
#12 0xa800297c in TaskItemLayout::removeTaskItem (this=0xa34e910, item=0xaa3db98) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:93
#13 0xa800e6de in TaskGroupItem::itemRemoved (this=0xa34eb00, groupableItem=0xa2f2e70) at ../../../../plasma/applets/tasks/taskgroupitem.cpp:521
#14 0xa800fb67 in TaskGroupItem::qt_metacall (this=0xa34eb00, _c=QMetaObject::InvokeMetaMethod, _id=31, _a=0xbfd34838) at ./taskgroupitem.moc:114
#15 0xb76f6303 in QMetaObject::activate (sender=0xa391a18, from_signal_index=22, to_signal_index=22, argv=0xbfd34838) at kernel/qobject.cpp:3112
#16 0xb76f6f42 in QMetaObject::activate (sender=0xa391a18, m=0xa810b154, local_signal_index=1, argv=0xbfd34838) at kernel/qobject.cpp:3186
#17 0xa80fd403 in TaskManager::TaskGroup::itemRemoved (this=0xa391a18, _t1=0xa2f2e70) at ./taskgroup.moc:152
#18 0xa80fdc2b in TaskManager::TaskGroup::remove (this=0xa391a18, item=0xa2f2e70) at ../../../libs/taskmanager/taskgroup.cpp:189
#19 0xa80e56ed in TaskManager::GroupManagerPrivate::removeTask (this=0xa1851d0, task=...) at ../../../libs/taskmanager/groupmanager.cpp:311
#20 0xa80e74fb in TaskManager::GroupManager::qt_metacall (this=0xa3639c0, _c=QMetaObject::InvokeMetaMethod, _id=11, _a=0xbfd34a08) at ./groupmanager.moc:105
#21 0xb76f6303 in QMetaObject::activate (sender=0xa38e4a8, from_signal_index=5, to_signal_index=5, argv=0xbfd34a08) at kernel/qobject.cpp:3112
#22 0xb76f6f42 in QMetaObject::activate (sender=0xa38e4a8, m=0xa810b31c, local_signal_index=1, argv=0xbfd34a08) at kernel/qobject.cpp:3186
#23 0xa8100e53 in TaskManager::TaskManager::taskRemoved (this=0xa38e4a8, _t1=...) at ./taskmanager.moc:162
#24 0xa8102bd2 in TaskManager::TaskManager::windowRemoved (this=0xa38e4a8, w=56623143) at ../../../libs/taskmanager/taskmanager.cpp:279
#25 0xa81043ff in TaskManager::TaskManager::qt_metacall (this=0xa38e4a8, _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0xbfd34b78) at ./taskmanager.moc:110
#26 0xb76f6303 in QMetaObject::activate (sender=0x9f7b3e8, from_signal_index=6, to_signal_index=6, argv=0xbfd34b78) at kernel/qobject.cpp:3112
#27 0xb76f6f42 in QMetaObject::activate (sender=0x9f7b3e8, m=0xb6f6b78c, local_signal_index=2, argv=0xbfd34b78) at kernel/qobject.cpp:3186
#28 0xb6f04533 in KWindowSystem::windowRemoved (this=0x9f7b3e8, _t1=56623143) at ./kwindowsystem.moc:127
#29 0xb6f07736 in KWindowSystemPrivate::removeClient (this=0x9fc6db8, w=56623143) at ../../kdeui/windowmanagement/kwindowsystem_x11.cpp:249
#30 0xb6f15a2f in NETRootInfo::update (this=0x9fc6dcc, dirty_props=0xbfd34d6c) at ../../kdeui/windowmanagement/netwm.cpp:2183
#31 0xb6f16571 in NETRootInfo::event (this=0x9fc6dcc, event=<value optimized out>, properties=0xbfd34df4, properties_size=5) at ../../kdeui/windowmanagement/netwm.cpp:2058
#32 0xb6f079d1 in KWindowSystemPrivate::x11Event (this=0x9fc6db8, ev=0xbfd3641c) at ../../kdeui/windowmanagement/kwindowsystem_x11.cpp:136
#33 0xb6db6226 in KAppX11HackWidget::publicx11Event (this=0x9eda690, _event=0xbfd3641c) at ../../kdeui/kernel/kapplication.cpp:900
#34 KApplication::x11EventFilter (this=0x9eda690, _event=0xbfd3641c) at ../../kdeui/kernel/kapplication.cpp:950
#35 0xb33734cf in PlasmaApp::x11EventFilter (this=0x9eda690, event=0xbfd3641c) at ../../../../plasma/shells/desktop/plasmaapp.cpp:490
#36 0xb63cdd5e in qt_x11EventFilter (ev=0xbfd3641c) at kernel/qapplication_x11.cpp:377
#37 0xb63dfe27 in QApplication::x11ProcessEvent (this=0x9eda690, event=0xbfd3641c) at kernel/qapplication_x11.cpp:3273
#38 0xb640bbc2 in x11EventSourceDispatch (s=0x9ee30f0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#39 0xb5f36b38 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#40 0xb5f3a3d0 in ?? () from /lib/libglib-2.0.so.0
#41 0xb5f3a503 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#42 0xb770c041 in QEventDispatcherGlib::processEvents (this=0x9ee0270, flags=...) at kernel/qeventdispatcher_glib.cpp:407
#43 0xb640b305 in QGuiEventDispatcherGlib::processEvents (this=0x9ee0270, flags=...) at kernel/qguieventdispatcher_glib.cpp:202
#44 0xb76df83a in QEventLoop::processEvents (this=0xbfd366d0, flags=...) at kernel/qeventloop.cpp:149
#45 0xb76dfc82 in QEventLoop::exec (this=0xbfd366d0, flags=...) at kernel/qeventloop.cpp:201
#46 0xb76e20d9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#47 0xb636b917 in QApplication::exec () at kernel/qapplication.cpp:3525
#48 0xb335d5cd in kdemain (argc=1, argv=0x9e87ac0) at ../../../../plasma/shells/desktop/main.cpp:50
#49 0x0804de99 in launch (argc=<value optimized out>, _name=<value optimized out>, args=<value optimized out>, cwd=0x0, envc=0, envs=0x9e71510 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x8050f87 "0") at ../../kinit/kinit.cpp:677
#50 0x0804ea0d in handle_launcher_request (sock=<value optimized out>, who=<value optimized out>) at ../../kinit/kinit.cpp:1169
#51 0x0804eea4 in handle_requests (waitForPid=<value optimized out>) at ../../kinit/kinit.cpp:1362
#52 0x0804f6b7 in main (argc=2, argv=0xbfd36f94, envp=0xbfd36fa0) at ../../kinit/kinit.cpp:1793

Reported using DrKonqi