Version:            (using KDE 4.2.85)
OS:                Linux
Installed from:    Ubuntu Packages

Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.2.85 (KDE 4.2.85 (KDE 4.3 Beta1))
Qt Version: 4.5.1
Operating System: Linux 2.6.28-12-generic i686
Distribution: Ubuntu 9.04

Hello, to recreate this bug:

1) open an application that takes a couple seconds to load (eg: I tested this on firefox, opera, and konqueror). click and open it.

2) while you are waiting for it to show up, click multiple times on the placeholder for the application in the taskbar presumably in your panel. (the ~application loading~ placeholder)

3) bam, plasma crashes and restarts itself.  results from Dr.Konqi below:

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 0 (LWP 11490)]

Thread 2 (Thread 0xa7a4cb90 (LWP 11494)):
#0  0xb7f69430 in __kernel_vsyscall ()
#1  0xb50340e5 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/tls/i686/cmov/libpthread.so.0
#2  0xb62842ed in pthread_cond_wait () from /lib/tls/i686/cmov/libc.so.6
#3  0xb64685b2 in QWaitCondition::wait (this=0x9090f98, mutex=0x9090f94, time=4294967295) at thread/qwaitcondition_unix.cpp:87
#4  0xb78c6ae2 in QHostInfoAgent::run (this=0x9090f88) at kernel/qhostinfo.cpp:260
#5  0xb646756e in QThreadPrivate::start (arg=0x9090f88) at thread/qthread_unix.cpp:189
#6  0xb50304ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#7  0xb627549e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb3c5f730 (LWP 11490)):
[KCrash Handler]
#6  0xa8608137 in TaskManager::Task::window () from /usr/lib/libtaskmanager.so.4
#7  0xb656bf0f in QObject::event (this=0x9e7b9d8, e=0x0) at kernel/qobject.cpp:1082
#8  0xb6e6f257 in QGraphicsWidget::event (this=0x9e7b9d8, event=0xbfb863cc) at graphicsview/qgraphicswidget.cpp:1340
#9  0xb67e6bcc in QApplicationPrivate::notify_helper (this=0x88b0e38, receiver=0x9e7b9d8, e=0xbfb863cc) at kernel/qapplication.cpp:4057
#10 0xb67eeede in QApplication::notify (this=0x889e460, receiver=0x9e7b9d8, e=0xbfb863cc) at kernel/qapplication.cpp:3604
#11 0xb7648c9d in KApplication::notify (this=0x889e460, receiver=0x9e7b9d8, event=0xbfb863cc) at /build/buildd/kde4libs-4.2.85/kdeui/kernel/kapplication.cpp:307
#12 0xb655b7ab in QCoreApplication::notifyInternal (this=0x889e460, receiver=0x9e7b9d8, event=0xbfb863cc) at kernel/qcoreapplication.cpp:610
#13 0xb658ab31 in QTimerInfoList::activateTimers (this=0x88b368c) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#14 0xb6587280 in timerSourceDispatch (source=0x88b3658) at kernel/qeventdispatcher_glib.cpp:164
#15 0xb4e2eb88 in IA__g_main_context_dispatch (context=0x88b2e60) at /build/buildd/glib2.0-2.20.1/glib/gmain.c:1814
#16 0xb4e320eb in g_main_context_iterate (context=0x88b2e60, block=1, dispatch=1, self=0x88ad418) at /build/buildd/glib2.0-2.20.1/glib/gmain.c:2448
#17 0xb4e32268 in IA__g_main_context_iteration (context=0x88b2e60, may_block=1) at /build/buildd/glib2.0-2.20.1/glib/gmain.c:2511
#18 0xb65871d8 in QEventDispatcherGlib::processEvents (this=0x88b0498, flags={i = -1078434488}) at kernel/qeventdispatcher_glib.cpp:324
#19 0xb6888765 in QGuiEventDispatcherGlib::processEvents (this=0x88b0498, flags={i = -1078434440}) at kernel/qguieventdispatcher_glib.cpp:202
#20 0xb6559dda in QEventLoop::processEvents (this=0xbfb865f0, flags={i = -1078434376}) at kernel/qeventloop.cpp:149
#21 0xb655a21a in QEventLoop::exec (this=0xbfb865f0, flags={i = -1078434312}) at kernel/qeventloop.cpp:200
#22 0xb655c6c9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#23 0xb67e6a47 in QApplication::exec () at kernel/qapplication.cpp:3526
#24 0xb7f05290 in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#25 0x08048712 in _start ()