Application: plasma-desktop (4.11.8)
KDE Platform Version: 4.13.0
Qt Version: 4.8.6
Operating System: Linux 3.13.0-24-generic x86_64
Distribution: Ubuntu 14.04 LTS

-- Information about the crash:
- What I was doing when the application crashed:
I opened firefox. It has 12 windows.  They opened but they do not group.
So from the menu I choose " do not allow thsi program to be grouped" and then "allow this program to be grouped". Icons grouped. Then I started to distribute the windows on the different desktops.

- Unusual behavior I noticed:
The 12 firefox icons did not group.

-- Backtrace:
Application: Plasma Desktop Shell (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f6fa96bb7c0 (LWP 2531))]

Thread 5 (Thread 0x7f6f7eae4700 (LWP 2532)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f6fa2368ffb in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f6fa2369039 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f6f9cc15182 in start_thread (arg=0x7f6f7eae4700) at pthread_create.c:312
#4  0x00007f6fa8fb630d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7f6ef2810700 (LWP 2538)):
#0  0x00007f6f9c545623 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f6f9c5459b9 in g_mutex_unlock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f6f9c503a20 in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f6f9c503f7b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f6f9c5040ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f6fa5b7e7be in QEventDispatcherGlib::processEvents (this=0x7f6eec0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#6  0x00007f6fa5b500af in QEventLoop::processEvents (this=this@entry=0x7f6ef280fde0, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f6fa5b503a5 in QEventLoop::exec (this=this@entry=0x7f6ef280fde0, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f6fa5a4cc5f in QThread::exec (this=this@entry=0x240a870) at thread/qthread.cpp:537
#9  0x00007f6fa5b31823 in QInotifyFileSystemWatcherEngine::run (this=0x240a870) at io/qfilesystemwatcher_inotify.cpp:265
#10 0x00007f6fa5a4f32f in QThreadPrivate::start (arg=0x240a870) at thread/qthread_unix.cpp:349
#11 0x00007f6f9cc15182 in start_thread (arg=0x7f6ef2810700) at pthread_create.c:312
#12 0x00007f6fa8fb630d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7f6ef114f700 (LWP 2539)):
#0  0x00007f6fa8fa8fbd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f6f9c503fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f6f9c5040ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f6fa5b7e7be in QEventDispatcherGlib::processEvents (this=0x7f6ee40008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#4  0x00007f6fa5b500af in QEventLoop::processEvents (this=this@entry=0x7f6ef114ede0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f6fa5b503a5 in QEventLoop::exec (this=this@entry=0x7f6ef114ede0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f6fa5a4cc5f in QThread::exec (this=this@entry=0x183d280) at thread/qthread.cpp:537
#7  0x00007f6fa5b31823 in QInotifyFileSystemWatcherEngine::run (this=0x183d280) at io/qfilesystemwatcher_inotify.cpp:265
#8  0x00007f6fa5a4f32f in QThreadPrivate::start (arg=0x183d280) at thread/qthread_unix.cpp:349
#9  0x00007f6f9cc15182 in start_thread (arg=0x7f6ef114f700) at pthread_create.c:312
#10 0x00007f6fa8fb630d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f6ee36c8700 (LWP 2545)):
#0  0x00007f6fa8fa8fbd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f6f9c503fe4 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f6f9c5040ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f6fa5b7e7be in QEventDispatcherGlib::processEvents (this=0x7f6edc0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#4  0x00007f6fa5b500af in QEventLoop::processEvents (this=this@entry=0x7f6ee36c7de0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f6fa5b503a5 in QEventLoop::exec (this=this@entry=0x7f6ee36c7de0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f6fa5a4cc5f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:537
#7  0x00007f6eebbcc027 in KCupsConnection::run() () from /usr/lib/libkcupslib.so
#8  0x00007f6fa5a4f32f in QThreadPrivate::start (arg=0x1affd00) at thread/qthread_unix.cpp:349
#9  0x00007f6f9cc15182 in start_thread (arg=0x7f6ee36c8700) at pthread_create.c:312
#10 0x00007f6fa8fb630d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f6fa96bb7c0 (LWP 2531)):
[KCrash Handler]
#6  size (this=0xf2e66ffffff6ae9) at ../../include/QtCore/../../src/corelib/tools/qlist.h:98
#7  size (this=0xf2e66ffffff6ae9) at ../../include/QtCore/../../src/corelib/tools/qlist.h:137
#8  QObjectPrivate::_q_reregisterTimers (this=0x9eb9d20, pointer=0xf2e66ffffff6ae9) at kernel/qobject.cpp:1525
#9  0x00007f6fa5b6ab2a in QObject::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at .moc/release-shared/moc_qobject.cpp:73
#10 0x00007f6fa5b6ac3d in QObject::qt_metacall (this=<optimized out>, _c=<optimized out>, _id=3, _a=<optimized out>) at .moc/release-shared/moc_qobject.cpp:111
#11 0x00007f6fa23db155 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#12 0x00007f6fa5b65a78 in QMetaObject::activate (sender=0x1c69e20, m=<optimized out>, local_signal_index=<optimized out>, argv=argv@entry=0x0) at kernel/qobject.cpp:3569
#13 0x00007f6fa5b66223 in QMetaObject::activate (sender=<optimized out>, signal_index=<optimized out>, argv=argv@entry=0x0) at kernel/qobject.cpp:3626
#14 0x00007f6fa77a307e in QDeclarativeVMEMetaObject::metaCall (this=0x8c2fe20, c=QMetaObject::WriteProperty, _id=<optimized out>, a=0x7fff5f969720) at qml/qdeclarativevmemetaobject.cpp:564
#15 0x00007f6fa77bec37 in QDeclarativePropertyPrivate::write (object=0x1c69e20, property=..., value=..., context=<optimized out>, flags=...) at qml/qdeclarativeproperty.cpp:1152
#16 0x00007f6fa77bf45c in QDeclarativePropertyPrivate::writeValueProperty (this=0x993f100, value=..., flags=...) at qml/qdeclarativeproperty.cpp:1088
#17 0x00007f6fa77bf512 in QDeclarativePropertyPrivate::write (that=..., value=..., flags=...) at qml/qdeclarativeproperty.cpp:1343
#18 0x00007f6fa77b9277 in QDeclarativeBinding::update (this=0x9259c50, flags=...) at qml/qdeclarativebinding.cpp:427
#19 0x00007f6fa77b80db in update (this=<optimized out>) at ../../include/QtDeclarative/private/../../../src/declarative/qml/qdeclarativebinding_p.h:208
#20 QDeclarativeBindingPrivate::emitValueChanged (this=<optimized out>) at qml/qdeclarativebinding.cpp:469
#21 0x00007f6fa77b7e63 in QDeclarativeExpression::qt_metacall (this=this@entry=0x9259c50, _c=_c@entry=QMetaObject::InvokeMetaMethod, _id=1, _a=0x7fff5f969b10) at .moc/release-shared/moc_qdeclarativeexpression.cpp:93
#22 0x00007f6fa78aefd0 in QDeclarativeBinding::qt_metacall (this=0x9259c50, _c=QMetaObject::InvokeMetaMethod, _id=<optimized out>, _a=<optimized out>) at .moc/release-shared/moc_qdeclarativebinding_p.cpp:85
#23 0x00007f6fa5b65a78 in QMetaObject::activate (sender=0x8f1fa00, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3569
#24 0x00007f6fa774c334 in QDeclarativeItem::setImplicitWidth (this=this@entry=0x8f1fa00, w=<optimized out>) at graphicsitems/qdeclarativeitem.cpp:3469
#25 0x00007f6f80f4a3de in TextLabel::updateImplicitSize (this=0x8f1fa00) at ../../../../../plasma/desktop/applets/tasks/support/textlabel.cpp:95
#26 0x00007f6f80f4a749 in TextLabel::setText (this=this@entry=0x8f1fa00, text=...) at ../../../../../plasma/desktop/applets/tasks/support/textlabel.cpp:69
#27 0x00007f6f80f44138 in TextLabel::qt_metacall (this=0x8f1fa00, _c=QMetaObject::WriteProperty, _id=1, _a=0x7fff5f969db0) at moc_textlabel.cpp:109
#28 0x00007f6fa77bec37 in QDeclarativePropertyPrivate::write (object=0x8f1fa00, property=..., value=..., context=<optimized out>, flags=...) at qml/qdeclarativeproperty.cpp:1152
#29 0x00007f6fa77bf45c in QDeclarativePropertyPrivate::writeValueProperty (this=0x76b15e0, value=..., flags=...) at qml/qdeclarativeproperty.cpp:1088
#30 0x00007f6fa77bf512 in QDeclarativePropertyPrivate::write (that=..., value=..., flags=...) at qml/qdeclarativeproperty.cpp:1343
#31 0x00007f6fa77b9277 in QDeclarativeBinding::update (this=0x9274d10, flags=...) at qml/qdeclarativebinding.cpp:427
#32 0x00007f6fa77b80db in update (this=<optimized out>) at ../../include/QtDeclarative/private/../../../src/declarative/qml/qdeclarativebinding_p.h:208
#33 QDeclarativeBindingPrivate::emitValueChanged (this=<optimized out>) at qml/qdeclarativebinding.cpp:469
#34 0x00007f6fa77b7e63 in QDeclarativeExpression::qt_metacall (this=this@entry=0x9274d10, _c=_c@entry=QMetaObject::InvokeMetaMethod, _id=1, _a=0x7fff5f96a1a0) at .moc/release-shared/moc_qdeclarativeexpression.cpp:93
#35 0x00007f6fa78aefd0 in QDeclarativeBinding::qt_metacall (this=0x9274d10, _c=QMetaObject::InvokeMetaMethod, _id=<optimized out>, _a=<optimized out>) at .moc/release-shared/moc_qdeclarativebinding_p.cpp:85
#36 0x00007f6fa5b65a78 in QMetaObject::activate (sender=0x99f00c0, m=<optimized out>, local_signal_index=<optimized out>, argv=argv@entry=0x0) at kernel/qobject.cpp:3569
#37 0x00007f6fa5b66223 in QMetaObject::activate (sender=<optimized out>, signal_index=<optimized out>, argv=argv@entry=0x0) at kernel/qobject.cpp:3626
#38 0x00007f6fa76f54c1 in QDeclarativeOpenMetaObject::setValue (this=0x915d6b0, id=id@entry=4, value=...) at util/qdeclarativeopenmetaobject.cpp:261
#39 0x00007f6fa77806f2 in setValue (val=..., id=4, this=0x99f00c0) at graphicsitems/qdeclarativevisualitemmodel.cpp:469
#40 QDeclarativeVisualDataModel::_q_itemsChanged (this=0x1c36d50, index=0, count=10, roles=...) at graphicsitems/qdeclarativevisualitemmodel.cpp:1226
#41 0x00007f6fa78ab7ed in QDeclarativeVisualDataModel::qt_static_metacall (_o=0x9eb9d20, _c=4294929129, _id=3, _a=0x7fff5f969520) at .moc/release-shared/moc_qdeclarativevisualitemmodel_p.cpp:406
#42 0x00007f6fa5b6587a in QMetaObject::activate (sender=sender@entry=0x1b3b9b0, m=m@entry=0x7f6fa5eb56a0 <QAbstractItemModel::staticMetaObject>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x0) at kernel/qobject.cpp:3539
#43 0x00007f6fa5baf5a3 in QAbstractItemModel::layoutChanged (this=this@entry=0x1b3b9b0) at .moc/release-shared/moc_qabstractitemmodel.cpp:176
#44 0x00007f6fa5b4aa89 in QAbstractItemModel::endMoveRows (this=0x1b3b9b0) at kernel/qabstractitemmodel.cpp:2673
#45 0x00007f6f813b8c9c in itemMoved (item=<optimized out>, this=<optimized out>) at ../../../libs/taskmanager/tasksmodel.cpp:524
#46 TaskManager::TasksModel::qt_static_metacall (_o=0x9eb9d20, _id=-38167, _a=0x7fff5f96a740, _c=<optimized out>) at ./tasksmodel.moc:135
#47 0x00007f6fa5b6587a in QMetaObject::activate (sender=sender@entry=0x1b3f960, m=m@entry=0x7f6f815d51e0 <TaskManager::TaskGroup::staticMetaObject>, local_signal_index=local_signal_index@entry=6, argv=argv@entry=0x7fff5f96a740) at kernel/qobject.cpp:3539
#48 0x00007f6f813abb22 in TaskManager::TaskGroup::itemPositionChanged (this=this@entry=0x1b3f960, _t1=_t1@entry=0x8992560) at ./taskgroup.moc:220
#49 0x00007f6f813ae719 in TaskManager::TaskGroup::moveItem (this=0x1b3f960, oldIndex=oldIndex@entry=8, newIndex=newIndex@entry=1) at ../../../libs/taskmanager/taskgroup.cpp:707
#50 0x00007f6f8138ec8a in TaskManager::AbstractSortingStrategy::check (this=<optimized out>, itemToCheck=<optimized out>) at ../../../libs/taskmanager/abstractsortingstrategy.cpp:148
#51 0x00007f6f813917ee in TaskManager::GroupManagerPrivate::addTask (this=this@entry=0x1b39190, task=task@entry=0x9967160) at ../../../libs/taskmanager/groupmanager.cpp:360
#52 0x00007f6f81392161 in TaskManager::GroupManagerPrivate::taskChanged (this=0x1b39190, task=0x9967160, changes=...) at ../../../libs/taskmanager/groupmanager.cpp:589
#53 0x00007f6f81395662 in TaskManager::GroupManager::qt_static_metacall (_o=<optimized out>, _id=<optimized out>, _a=<optimized out>, _c=<optimized out>) at ./groupmanager.moc:86
#54 0x00007f6fa5b6587a in QMetaObject::activate (sender=sender@entry=0x1b37e20, m=m@entry=0x7f6f815d54c0 <TaskManager::TaskManager::staticMetaObject>, local_signal_index=local_signal_index@entry=6, argv=argv@entry=0x7fff5f96aa00) at kernel/qobject.cpp:3539
#55 0x00007f6f813b4067 in TaskManager::TaskManager::windowChanged (this=this@entry=0x1b37e20, _t1=0x9967160, _t2=...) at ./taskmanager.moc:228
#56 0x00007f6f813b41fb in TaskManager::TaskManager::taskChanged (this=0x1b37e20, changes=...) at ../../../libs/taskmanager/taskmanager.cpp:387
#57 0x00007f6f813b62c1 in TaskManager::TaskManager::qt_static_metacall (_o=0x9eb9d20, _id=-38167, _a=0x3, _c=<optimized out>) at ./taskmanager.moc:110
#58 0x00007f6fa5b6587a in QMetaObject::activate (sender=sender@entry=0x9967160, m=m@entry=0x7f6f815d3060 <TaskManager::Task::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fff5f96abe0) at kernel/qobject.cpp:3539
#59 0x00007f6f813a3892 in TaskManager::Task::changed (this=this@entry=0x9967160, _t1=...) at ./task.moc:238
#60 0x00007f6f813a4547 in TaskManager::Task::refresh (this=this@entry=0x9967160, dirty=...) at ../../../libs/taskmanager/task.cpp:162
#61 0x00007f6f813a4767 in TaskManager::Task::timerEvent (this=0x9967160) at ../../../libs/taskmanager/task.cpp:65
#62 0x00007f6fa5b69a31 in QObject::event (this=0x9967160, e=<optimized out>) at kernel/qobject.cpp:1156
#63 0x00007f6fa4eeae2c in QApplicationPrivate::notify_helper (this=this@entry=0x1473790, receiver=receiver@entry=0x9967160, e=e@entry=0x7fff5f96b070) at kernel/qapplication.cpp:4567
#64 0x00007f6fa4ef14a0 in QApplication::notify (this=this@entry=0x145b390, receiver=receiver@entry=0x9967160, e=e@entry=0x7fff5f96b070) at kernel/qapplication.cpp:4353
#65 0x00007f6fa6816baa in KApplication::notify (this=0x145b390, receiver=0x9967160, event=0x7fff5f96b070) at ../../kdeui/kernel/kapplication.cpp:311
#66 0x00007f6fa5b514dd in QCoreApplication::notifyInternal (this=0x145b390, receiver=0x9967160, event=0x7fff5f96b070) at kernel/qcoreapplication.cpp:953
#67 0x00007f6fa5b81323 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#68 QTimerInfoList::activateTimers (this=0x1474d80) at kernel/qeventdispatcher_unix.cpp:621
#69 0x00007f6fa5b7e629 in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:193
#70 idleTimerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:240
#71 0x00007f6f9c503e04 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#72 0x00007f6f9c504048 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#73 0x00007f6f9c5040ec in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#74 0x00007f6fa5b7e7a1 in QEventDispatcherGlib::processEvents (this=0x13ecaf0, flags=...) at kernel/qeventdispatcher_glib.cpp:434
#75 0x00007f6fa4f8cbb6 in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#76 0x00007f6fa5b500af in QEventLoop::processEvents (this=this@entry=0x7fff5f96b2e0, flags=...) at kernel/qeventloop.cpp:149
#77 0x00007f6fa5b503a5 in QEventLoop::exec (this=this@entry=0x7fff5f96b2e0, flags=...) at kernel/qeventloop.cpp:204
#78 0x00007f6fa5b55b79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#79 0x00007f6fa4ee937c in QApplication::exec () at kernel/qapplication.cpp:3828
#80 0x00007f6fa92bd66c in kdemain (argc=1, argv=0x7fff5f96b538) at ../../../../plasma/desktop/shell/main.cpp:126
#81 0x00007f6fa8edcec5 in __libc_start_main (main=0x4006e0 <main(int, char**)>, argc=1, argv=0x7fff5f96b538, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff5f96b528) at libc-start.c:287
#82 0x000000000040070e in _start ()

Reported using DrKonqi