Version:            (using KDE 4.2.0)
Compiler:          gcc4 
OS:                Linux
Installed from:    Mandriva RPMs

All I did was right click on the taskbar and click on "Do not allow this application to be grouped" For dolphin opened in two instances grouped as one and received this :

Application: Plasma Workspace (plasma), signal SIGSEGV
[Current thread is 1 (Thread 0xb4bbd6d0 (LWP 15660))]

Thread 3 (Thread 0xa9221b90 (LWP 15661)):
#0  0xffffe424 in __kernel_vsyscall ()
#1  0xb5171c45 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i686/libpthread.so.0
#2  0xb7feb8ed in pthread_cond_wait () from /lib/i686/libc.so.6
#3  0xb680091b in QWaitCondition::wait (this=0x9123c48, mutex=0x9123c44, time=4294967295) at thread/qwaitcondition_unix.cpp:82
#4  0xb5220f74 in QHostInfoAgent::run (this=0x9123c38) at kernel/qhostinfo.cpp:255
#5  0xb67ff80f in QThreadPrivate::start (arg=0x9123c38) at thread/qthread_unix.cpp:184
#6  0xb516e315 in start_thread () from /lib/i686/libpthread.so.0
#7  0xb7fde26e in clone () from /lib/i686/libc.so.6

Thread 2 (Thread 0xa89deb90 (LWP 15662)):
#0  0xffffe424 in __kernel_vsyscall ()
#1  0xb5171c45 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i686/libpthread.so.0
#2  0xb7feb8ed in pthread_cond_wait () from /lib/i686/libc.so.6
#3  0xb680091b in QWaitCondition::wait (this=0x8c6a7a8, mutex=0x8c6a7a4, time=4294967295) at thread/qwaitcondition_unix.cpp:82
#4  0xa9bb1fae in RenderThread::run (this=0x8c6a79c) at /usr/src/debug/kdebase-workspace-4.2.0/plasma/wallpapers/image/renderthread.cpp:91
#5  0xb67ff80f in QThreadPrivate::start (arg=0x8c6a79c) at thread/qthread_unix.cpp:184
#6  0xb516e315 in start_thread () from /lib/i686/libpthread.so.0
#7  0xb7fde26e in clone () from /lib/i686/libc.so.6

Thread 1 (Thread 0xb4bbd6d0 (LWP 15660)):
[KCrash Handler]
#6  0xb69139d9 in QMetaObject::activate (sender=0x8c40dd8, m=0xa967ec5c, local_signal_index=0, argv=0xbfaf9480) at kernel/qobject.cpp:3123
#7  0xa9646245 in TaskManager::AbstractGroupingStrategy::groupRemoved (this=0x8c40dd8, _t1=0x93fd740) at /usr/src/debug/kdebase-workspace-4.2.0/build/libs/taskmanager/abstractgroupingstrategy.moc:89
#8  0xa9646c99 in TaskManager::AbstractGroupingStrategy::closeGroup (this=0x8c40dd8, group=0x93fd740) at /usr/src/debug/kdebase-workspace-4.2.0/libs/taskmanager/abstractgroupingstrategy.cpp:143
#9  0xa96511fc in TaskManager::ProgramGroupingStrategy::toggleGrouping (this=0x8c40dd8) at /usr/src/debug/kdebase-workspace-4.2.0/libs/taskmanager/strategies/programgroupingstrategy.cpp:109
#10 0xa96512d5 in TaskManager::ProgramGroupingStrategy::qt_metacall (this=0x8c40dd8, _c=QMetaObject::InvokeMetaMethod, _id=16, _a=0xbfaf9640)
    at /usr/src/debug/kdebase-workspace-4.2.0/build/libs/taskmanager/programgroupingstrategy.moc:69
#11 0xb6912125 in QMetaObject::activate (sender=0x9112810, from_signal_index=5, to_signal_index=6, argv=0xbfaf9640) at kernel/qobject.cpp:3055
#12 0xb691257b in QMetaObject::activate (sender=0x9112810, m=0xb7447508, from_local_signal_index=1, to_local_signal_index=2, argv=0xbfaf9640) at kernel/qobject.cpp:3147
#13 0xb6b951a5 in QAction::triggered (this=0x9112810, _t1=false) at .moc/release-shared/moc_qaction.cpp:236
#14 0xb6b967d7 in QAction::activate (this=0x9112810, event=QAction::Trigger) at kernel/qaction.cpp:1155
#15 0xb7018947 in QMenuPrivate::activateCausedStack (this=0x92cfc98, causedStack=@0xbfaf9718, action=0x9112810, action_e=QAction::Trigger, self=true) at widgets/qmenu.cpp:957
#16 0xb701f3b4 in QMenuPrivate::activateAction (this=0x92cfc98, action=0x9112810, action_e=QAction::Trigger, self=true) at widgets/qmenu.cpp:1053
#17 0xb701fe84 in QMenu::mouseReleaseEvent (this=0xbfafa550, e=0xbfaf9c98) at widgets/qmenu.cpp:2247
#18 0xb6bf4dfd in QWidget::event (this=0xbfafa550, event=0xbfaf9c98) at kernel/qwidget.cpp:7511
#19 0xb7022164 in QMenu::event (this=0xbfafa550, e=0xbfaf9c98) at widgets/qmenu.cpp:2346
#20 0xb6b9ba0c in QApplicationPrivate::notify_helper (this=0x8b21e18, receiver=0xbfafa550, e=0xbfaf9c98) at kernel/qapplication.cpp:4051
#21 0xb6ba4ca2 in QApplication::notify (this=0x8b1f460, receiver=0xbfafa550, e=0xbfaf9c98) at kernel/qapplication.cpp:3753
#22 0xb7861300 in KApplication::notify (this=0x8b1f460, receiver=0xbfafa550, event=0xbfaf9c98) at /usr/src/debug/kdelibs-4.2.0/kdeui/kernel/kapplication.cpp:307
#23 0xb68fb61e in QCoreApplication::notifyInternal (this=0x8b1f460, receiver=0xbfafa550, event=0xbfaf9c98) at kernel/qcoreapplication.cpp:597
#24 0xb6ba3ac1 in QApplicationPrivate::sendMouseEvent (receiver=0xbfafa550, event=0xbfaf9c98, alienWidget=0x0, nativeWidget=0xbfafa550, buttonDown=0xb7465100, lastMouseReceiver=@0xb7465104)
    at ../../src/corelib/kernel/qcoreapplication.h:211
#25 0xb6c1757a in QETWidget::translateMouseEvent (this=0xbfafa550, event=0xbfafa2ac) at kernel/qapplication_x11.cpp:4348
#26 0xb6c1681c in QApplication::x11ProcessEvent (this=0x8b1f460, event=0xbfafa2ac) at kernel/qapplication_x11.cpp:3410
#27 0xb6c40764 in x11EventSourceDispatch (s=0x8b27000, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:141
#28 0xb4f98c8a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#29 0xb4f9c2f4 in ?? () from /usr/lib/libglib-2.0.so.0
#30 0xb4f9c47f in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#31 0xb69284aa in QEventDispatcherGlib::processEvents (this=0x8af4208, flags={i = -1079008168}) at kernel/qeventdispatcher_glib.cpp:318
#32 0xb6c3feba in QGuiEventDispatcherGlib::processEvents (this=0x8af4208, flags={i = -1079008120}) at kernel/qguieventdispatcher_glib.cpp:197
#33 0xb68f9be3 in QEventLoop::processEvents (this=0xbfafa4fc, flags={i = -1079008056}) at kernel/qeventloop.cpp:144
#34 0xb68fa031 in QEventLoop::exec (this=0xbfafa4fc, flags={i = -1079007996}) at kernel/qeventloop.cpp:195
#35 0xb7021f93 in QMenu::exec (this=0xbfafa550, p=@0xbfafa564, action=0x0) at widgets/qmenu.cpp:1986
#36 0xa9625951 in TaskGroupItem::contextMenuEvent (this=0x940e758, e=0xbfafaa9c) at /usr/src/debug/kdebase-workspace-4.2.0/plasma/applets/tasks/taskgroupitem.cpp:346
#37 0xb71e7db8 in QGraphicsItem::sceneEvent (this=0x940e760, event=0xbfafaa9c) at graphicsview/qgraphicsitem.cpp:4702
#38 0xb7237567 in QGraphicsWidget::sceneEvent (this=0x940e758, event=0xbfafaa9c) at graphicsview/qgraphicswidget.cpp:1084
#39 0xb720cf54 in QGraphicsScenePrivate::sendEvent (this=0x8b9ff58, item=0x940e760, event=0xbfafaa9c) at graphicsview/qgraphicsscene.cpp:1143
#40 0xb7217adf in QGraphicsScene::contextMenuEvent (this=0x8bab440, contextMenuEvent=0xbfafaa9c) at graphicsview/qgraphicsscene.cpp:3781
#41 0xb7216863 in QGraphicsScene::event (this=0x8bab440, event=0xbfafaa9c) at graphicsview/qgraphicsscene.cpp:3591
#42 0xb6b9ba0c in QApplicationPrivate::notify_helper (this=0x8b21e18, receiver=0x8bab440, e=0xbfafaa9c) at kernel/qapplication.cpp:4051
#43 0xb6ba4146 in QApplication::notify (this=0x8b1f460, receiver=0x8bab440, e=0xbfafaa9c) at kernel/qapplication.cpp:3598
#44 0xb7861300 in KApplication::notify (this=0x8b1f460, receiver=0x8bab440, event=0xbfafaa9c) at /usr/src/debug/kdelibs-4.2.0/kdeui/kernel/kapplication.cpp:307
#45 0xb68fb61e in QCoreApplication::notifyInternal (this=0x8b1f460, receiver=0x8bab440, event=0xbfafaa9c) at kernel/qcoreapplication.cpp:597
#46 0xb7225668 in QGraphicsView::contextMenuEvent (this=0x8c46380, event=0xbfafb050) at ../../src/corelib/kernel/qcoreapplication.h:208
#47 0xb6bf5473 in QWidget::event (this=0x8c46380, event=0xbfafb050) at kernel/qwidget.cpp:7670
#48 0xb6fd2af5 in QFrame::event (this=0x8c46380, e=0xbfafb050) at widgets/qframe.cpp:554
#49 0xb7077080 in QAbstractScrollArea::viewportEvent (this=0x8c46380, e=0x10) at widgets/qabstractscrollarea.cpp:957
#50 0xb7227c18 in QGraphicsView::viewportEvent (this=0x8c46380, event=0xbfafb050) at graphicsview/qgraphicsview.cpp:2928
#51 0xb70796f6 in QAbstractScrollAreaFilter::eventFilter (this=0x91aa0a0, o=0x8c3e830, e=0xbfafb050) at widgets/qabstractscrollarea_p.h:95
#52 0xb68fa7be in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x8b21e18, receiver=0x8c3e830, event=0xbfafb050) at kernel/qcoreapplication.cpp:713
#53 0xb6b9b9df in QApplicationPrivate::notify_helper (this=0x8b21e18, receiver=0x8c3e830, e=0xbfafb050) at kernel/qapplication.cpp:4047
#54 0xb6ba474c in QApplication::notify (this=0x8b1f460, receiver=0x8c3e830, e=0xbfafb050) at kernel/qapplication.cpp:3840
#55 0xb7861300 in KApplication::notify (this=0x8b1f460, receiver=0x8c3e830, event=0xbfafb050) at /usr/src/debug/kdelibs-4.2.0/kdeui/kernel/kapplication.cpp:307
#56 0xb68fb61e in QCoreApplication::notifyInternal (this=0x8b1f460, receiver=0x8c3e830, event=0xbfafb050) at kernel/qcoreapplication.cpp:597
#57 0xb6ba714d in QCoreApplication::sendSpontaneousEvent (receiver=0x8c3e830, event=0x10) at ../../src/corelib/kernel/qcoreapplication.h:211
#58 0xb6c17a62 in QETWidget::translateMouseEvent (this=0x8c46380, event=0xbfafb63c) at kernel/qapplication_x11.cpp:4420
#59 0xb6c1681c in QApplication::x11ProcessEvent (this=0x8b1f460, event=0xbfafb63c) at kernel/qapplication_x11.cpp:3410
#60 0xb6c40764 in x11EventSourceDispatch (s=0x8b27000, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:141
#61 0xb4f98c8a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#62 0xb4f9c2f4 in ?? () from /usr/lib/libglib-2.0.so.0
#63 0xb4f9c47f in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#64 0xb69284aa in QEventDispatcherGlib::processEvents (this=0x8af4208, flags={i = -1079003160}) at kernel/qeventdispatcher_glib.cpp:318
#65 0xb6c3feba in QGuiEventDispatcherGlib::processEvents (this=0x8af4208, flags={i = -1079003112}) at kernel/qguieventdispatcher_glib.cpp:197
#66 0xb68f9be3 in QEventLoop::processEvents (this=0xbfafb890, flags={i = -1079003048}) at kernel/qeventloop.cpp:144
#67 0xb68fa031 in QEventLoop::exec (this=0xbfafb890, flags={i = -1079002984}) at kernel/qeventloop.cpp:195
#68 0xb68fc596 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:875
#69 0xb6b9b874 in QApplication::exec () at kernel/qapplication.cpp:3526
#70 0xb8080a81 in kdemain (argc=1, argv=0xbfafba34) at /usr/src/debug/kdebase-workspace-4.2.0/plasma/shells/desktop/main.cpp:54
#71 0x0804856f in main (argc=) at /usr/src/debug/kdebase-workspace-4.2.0/build/plasma/shells/desktop/plasma_qgv_dummy.cpp:3