Version:           KDE 4.2 RC1 (using Devel)
Compiler:          gcc 4.3 
OS:                Linux
Installed from:    Compiled sources

I selected 5 consecutive messages in an IMAP folder. Immediately on typing Shift-Delete, it crashed. On restarting KMail, the first two messages had been deleted but the others remained.

Application: KMail (kmail), signal SIGABRT
0xb7fb67f2 in ?? () from /lib/ld-linux.so.2
[Current thread is 0 (LWP 6334)]

Thread 3 (Thread 0xb0f3eb90 (LWP 6339)):
#0  0xb7fb67f2 in ?? () from /lib/ld-linux.so.2
#1  0xb5f899f1 in select () from /lib/i686/cmov/libc.so.6
#2  0xb6aee120 in QProcessManager::run (this=0x92585f0) at io/qprocess_unix.cpp:301
#3  0xb6a2f9b0 in QThreadPrivate::start (arg=0x92585f0) at thread/qthread_unix.cpp:185
#4  0xb69ab4c0 in start_thread () from /lib/i686/cmov/libpthread.so.0
#5  0xb5f9161e in clone () from /lib/i686/cmov/libc.so.6

Thread 2 (Thread 0xb0711b90 (LWP 12334)):
#0  0xb7fb67f2 in ?? () from /lib/ld-linux.so.2
#1  0xb69af352 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/i686/cmov/libpthread.so.0
#2  0xb6a3071c in QWaitCondition::wait (this=0x9635480, mutex=0x963547c, time=30000) at thread/qwaitcondition_unix.cpp:80
#3  0xb6a26c66 in QThreadPoolThread::run (this=0x986b2d0) at concurrent/qthreadpool.cpp:135
#4  0xb6a2f9b0 in QThreadPrivate::start (arg=0x986b2d0) at thread/qthread_unix.cpp:185
#5  0xb69ab4c0 in start_thread () from /lib/i686/cmov/libpthread.so.0
#6  0xb5f9161e in clone () from /lib/i686/cmov/libc.so.6

Thread 1 (Thread 0xb40e86c0 (LWP 6334)):
[KCrash Handler]
#6  0xb7fb67f2 in ?? () from /lib/ld-linux.so.2
#7  0xb5edc640 in raise () from /lib/i686/cmov/libc.so.6
#8  0xb5ede018 in abort () from /lib/i686/cmov/libc.so.6
#9  0xb6a28895 in qt_message_output (msgType=QtFatalMsg, 
    buf=0xbfbcc7f0 "ASSERT: \"dyingMessage->isViewable()\" in file /home/david/src/svn/4.2/kdepim/kmail/messagelistview/core/model.cpp, line 2925") at global/qglobal.cpp:2102
#10 0xb6a28946 in qFatal (msg=0xb6b53338 "ASSERT: \"%s\" in file %s, line %d") at global/qglobal.cpp:2303
#11 0xb6a289d5 in qt_assert (assertion=0xb78cfd3c "dyingMessage->isViewable()", file=0xb78cf658 "/home/david/src/svn/4.2/kdepim/kmail/messagelistview/core/model.cpp", line=2925)
    at global/qglobal.cpp:1872
#12 0xb77c7fb1 in KMail::MessageListView::Core::Model::viewItemJobStepInternalForJobPass1Cleanup (this=0x949ca38, job=0x9945610, tStart=@0xbfbcea14)
    at /home/david/src/svn/4.2/kdepim/kmail/messagelistview/core/model.cpp:2925
#13 0xb77c9c3e in KMail::MessageListView::Core::Model::viewItemJobStepInternalForJob (this=0x949ca38, job=0x9945610, tStart=@0xbfbcea14)
    at /home/david/src/svn/4.2/kdepim/kmail/messagelistview/core/model.cpp:3305
#14 0xb77ca66c in KMail::MessageListView::Core::Model::viewItemJobStepInternal (this=0x949ca38) at /home/david/src/svn/4.2/kdepim/kmail/messagelistview/core/model.cpp:3507
#15 0xb77cb35a in KMail::MessageListView::Core::Model::viewItemJobStep (this=0x949ca38) at /home/david/src/svn/4.2/kdepim/kmail/messagelistview/core/model.cpp:3666
#16 0xb731250c in KMail::MessageListView::Core::Model::qt_metacall (this=0x949ca38, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfbcecc8)
    at /home/david/src/svn/obj/4.2/kdepim/kmail/moc_model.cpp:75
#17 0xb6b1be9a in QMetaObject::activate (sender=0x948c408, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3028
#18 0xb6b1c412 in QMetaObject::activate (sender=0x948c408, m=0xb6ba6e24, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3101
#19 0xb6b52847 in QTimer::timeout (this=0x948c408) at .moc/release-shared/moc_qtimer.cpp:126
#20 0xb6b234de in QTimer::timerEvent (this=0x948c408, e=0xbfbcf16c) at kernel/qtimer.cpp:257
#21 0xb6b1877f in QObject::event (this=0x948c408, e=0xbfbcf16c) at kernel/qobject.cpp:1120
#22 0xb626660c in QApplicationPrivate::notify_helper (this=0x9254e70, receiver=0x948c408, e=0xbfbcf16c) at kernel/qapplication.cpp:3803
#23 0xb626d6ee in QApplication::notify (this=0xbfbcf478, receiver=0x948c408, e=0xbfbcf16c) at kernel/qapplication.cpp:3393
#24 0xb7df906d in KApplication::notify (this=0xbfbcf478, receiver=0x948c408, event=0xbfbcf16c) at /home/david/src/svn/4.2/kdelibs/kdeui/kernel/kapplication.cpp:307
#25 0xb6b0a641 in QCoreApplication::notifyInternal (this=0xbfbcf478, receiver=0x948c408, event=0xbfbcf16c) at kernel/qcoreapplication.cpp:583
#26 0xb6b342d1 in QTimerInfoList::activateTimers (this=0x9257edc) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:209
#27 0xb6b30e50 in timerSourceDispatch (source=0x9257ea8) at kernel/qeventdispatcher_glib.cpp:160
#28 0xb471e1b8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#29 0xb4721853 in ?? () from /usr/lib/libglib-2.0.so.0
#30 0x09257298 in ?? ()
#31 0x00000000 in ?? ()