Application: plasma-desktop (0.3)
KDE Version: 4.3.69 (KDE 4.3.69 (KDE 4.4 >= 20090923)) (Compiled from sources)
Qt Version: 4.5.1
Operating System: Linux 2.6.29-gentoo-r5 i686

What I was doing when the application crashed:
Was just playing around with the new "AddWidget" interface, and was trying to drag the taskmanager widget on the panel. The dragging operation seemed to get in trouble, since you couldn't see the paste area highlighted on the panel, (like it is used to do, when you drag a widget over it). Then I got this crash 

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 0 (LWP 28393)]

Thread 2 (Thread 0xa840bb90 (LWP 28396)):
#0  0xb7f8b424 in __kernel_vsyscall ()
#1  0xb7d4dbf5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb7dd60e4 in QWaitConditionPrivate::wait (this=0x993e740, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#3  0xb7dd5be3 in QWaitCondition::wait (this=0x99f1538, mutex=0x99f1534, time=4294967295) at thread/qwaitcondition_unix.cpp:159
#4  0xb76cbddb in QHostInfoAgent::run (this=0x99f1528) at kernel/qhostinfo.cpp:260
#5  0xb7dd57bf in QThreadPrivate::start (arg=0x99f1528) at thread/qthread_unix.cpp:189
#6  0xb7d4a16f in start_thread () from /lib/libpthread.so.0
#7  0xb66bddce in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb5fc4700 (LWP 28393)):
[KCrash Handler]
#5  0x09f28ab8 in ?? ()
#6  0xb39fe53b in AppletIconWidget::mouseMoveEvent (this=0x9f5bed0, event=0xbf8a2700) at /opt/kde/kdebase/workspace/libs/plasmagenericshell/widgetsExplorer/appleticon.cpp:92
#7  0xb7033114 in QGraphicsItem::sceneEvent (this=0x9f5bed8, event=0xbf8a2700) at graphicsview/qgraphicsitem.cpp:5010
#8  0xb706f3e9 in QGraphicsWidget::sceneEvent (this=0x9f5bed0, event=0xbf8a2700) at graphicsview/qgraphicswidget.cpp:1110
#9  0xb703e732 in QGraphicsScenePrivate::sendEvent (this=0x972c208, item=0x9f5bed8, event=0xbf8a2700) at graphicsview/qgraphicsscene.cpp:1159
#10 0xb7044bee in QGraphicsScenePrivate::sendMouseEvent (this=0x972c208, mouseEvent=0xbf8a2700) at graphicsview/qgraphicsscene.cpp:1230
#11 0xb7050bc3 in QGraphicsScene::mouseMoveEvent (this=0x96a3448, mouseEvent=0xbf8a2700) at graphicsview/qgraphicsscene.cpp:4424
#12 0xb704e515 in QGraphicsScene::event (this=0x96a3448, event=0xbf8a2700) at graphicsview/qgraphicsscene.cpp:3807
#13 0xb69bc24d in QApplicationPrivate::notify_helper (this=0x9645af8, receiver=0x96a3448, e=0xbf8a2700) at kernel/qapplication.cpp:4057
#14 0xb69bc601 in QApplication::notify (this=0x9638e98, receiver=0x96a3448, e=0xbf8a2700) at kernel/qapplication.cpp:3604
#15 0xb74343f1 in KApplication::notify (this=0x9638e98, receiver=0x96a3448, event=0xbf8a2700) at /opt/kde/kdelibs/kdeui/kernel/kapplication.cpp:302
#16 0xb7eca683 in QCoreApplication::notifyInternal (this=0x9638e98, receiver=0x96a3448, event=0xbf8a2700) at kernel/qcoreapplication.cpp:606
#17 0xb7ece211 in QCoreApplication::sendEvent (receiver=0x96a3448, event=0xbf8a2700) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#18 0xb706440b in QGraphicsViewPrivate::mouseMoveEventHandler (this=0xa062058, event=0xbf8a3004) at graphicsview/qgraphicsview.cpp:605
#19 0xb70651a6 in QGraphicsView::mouseMoveEvent (this=0x9ddb2b8, event=0xbf8a3004) at graphicsview/qgraphicsview.cpp:3299
#20 0xb6a1d262 in QWidget::event (this=0x9ddb2b8, event=0xbf8a3004) at kernel/qwidget.cpp:7506
#21 0xb6e2fb30 in QFrame::event (this=0x9ddb2b8, e=0xbf8a3004) at widgets/qframe.cpp:559
#22 0xb6ecd85b in QAbstractScrollArea::viewportEvent (this=0x9ddb2b8, e=0xbf8a3004) at widgets/qabstractscrollarea.cpp:962
#23 0xb705e423 in QGraphicsView::viewportEvent (this=0x9ddb2b8, event=0xbf8a3004) at graphicsview/qgraphicsview.cpp:2897
#24 0xb6ed044a in QAbstractScrollAreaPrivate::viewportEvent (this=0xa062058, event=0xbf8a3004) at widgets/qabstractscrollarea_p.h:100
#25 0xb6ed0478 in QAbstractScrollAreaFilter::eventFilter (this=0x9f01938, o=0xa029468, e=0xbf8a3004) at widgets/qabstractscrollarea_p.h:111
#26 0xb7ec8a48 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x9645af8, receiver=0xa029468, event=0xbf8a3004) at kernel/qcoreapplication.cpp:726
#27 0xb69bc22a in QApplicationPrivate::notify_helper (this=0x9645af8, receiver=0xa029468, e=0xbf8a3004) at kernel/qapplication.cpp:4053
#28 0xb69bcfd0 in QApplication::notify (this=0x9638e98, receiver=0xa029468, e=0xbf8a3004) at kernel/qapplication.cpp:3759
#29 0xb74343f1 in KApplication::notify (this=0x9638e98, receiver=0xa029468, event=0xbf8a3004) at /opt/kde/kdelibs/kdeui/kernel/kapplication.cpp:302
#30 0xb7eca683 in QCoreApplication::notifyInternal (this=0x9638e98, receiver=0xa029468, event=0xbf8a3004) at kernel/qcoreapplication.cpp:606
#31 0xb69c7f27 in QCoreApplication::sendSpontaneousEvent (receiver=0xa029468, event=0xbf8a3004) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#32 0xb69c0fba in QApplicationPrivate::sendMouseEvent (receiver=0xa029468, event=0xbf8a3004, alienWidget=0xa029468, nativeWidget=0xa0910e8, buttonDown=0xb71a9da0, lastMouseReceiver=@0xb71a9da4)
    at kernel/qapplication.cpp:2925
#33 0xb6a3e5ae in QETWidget::translateMouseEvent (this=0xa0910e8, event=0xbf8a45c0) at kernel/qapplication_x11.cpp:4448
#34 0xb6a3f6cf in QApplication::x11ProcessEvent (this=0x9638e98, event=0xbf8a45c0) at kernel/qapplication_x11.cpp:3444
#35 0xb6a6a711 in x11EventSourceDispatch (s=0x96483a0, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#36 0xb65305a1 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#37 0xb6533aeb in ?? () from /usr/lib/libglib-2.0.so.0
#38 0x09647c20 in ?? ()
#39 0x00000000 in ?? ()

Reported using DrKonqi