Version:           1.9.51 (using 4.00.80 (KDE 4.0.80 >= (KDE 4.1 Beta1), compiled sources)
Compiler:          gcc
OS:                Linux (i686) release 2.6.24-gentoo-r8

Today, after I did the following steps in Kmail (with an IMAP account), it crashed with the backtrace below. Regrettably I was not able to reproduce this crash so far. I use kdepimlibs r812282 and kdepim r812462

1) Switch standard layout to "horizontal 3 pane layout" [Configure KMail -> Appearance -> Layout -> Show message preview pane next to message list]
2) Move the borders of the message preview pane
3) Switch from long folder list to short folder list [Configure KMail -> Appearance -> Layout -> Short folder list]
4) read some mail
5) Switch back to standard layout but still keep short folder list
6) move borders of message preview pane
7) Switch back to long folder list

Application: Kontact (kontact), signal SIGSEGV
Using host libthread_db library "/lib/libthread_db.so.1".
[Thread debugging using libthread_db enabled]
[New Thread 0xb4aba6f0 (LWP 31761)]
[New Thread 0xb0865b90 (LWP 31836)]
[KCrash handler]
#6  0xb18012f5 in KMail::ISubject::notify (this=0x8bbeea4)
    at /home/kde-devel/kde/src/KDE/kdepim/kmail/isubject.cpp:30
#7  0xb14b4a90 in KMMessage::updateBodyPart (this=0x8bbee88, 
    partSpecifier=@0xbfe37bb0, data=@0x8de7800)
    at /home/kde-devel/kde/src/KDE/kdepim/kmail/kmmessage.cpp:4178
#8  0xb17dd697 in KMail::ImapJob::slotGetMessageResult (this=0x8ad2ac8, 
    job=0x8d09120) at /home/kde-devel/kde/src/KDE/kdepim/kmail/imapjob.cpp:416
#9  0xb17de374 in KMail::ImapJob::qt_metacall (this=0x8ad2ac8, 
    _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbfe37ccc)
    at /home/kde-devel/kde/build/KDE/kdepim/kmail/imapjob.moc:81
#10 0xb7e82530 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#11 0xb7e82c92 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#12 0xb7bf8d68 in KJob::result (this=0x8d09120, _t1=0x8d09120)
    at /home/kde-devel/kde/build/KDE/kdelibs/kdecore/kjob.moc:186
#13 0xb7bf92e8 in KJob::emitResult (this=0x8d09120)
    at /home/kde-devel/kde/src/KDE/kdelibs/kdecore/jobs/kjob.cpp:290
#14 0xb764a91c in KIO::SimpleJob::slotFinished (this=0x8d09120)
    at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/job.cpp:491
#15 0xb764aceb in KIO::TransferJob::slotFinished (this=0x8d09120)
    at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/job.cpp:961
#16 0xb7651ca3 in KIO::TransferJob::qt_metacall (this=0x8d09120, 
    _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0xbfe37ef8)
    at /home/kde-devel/kde/build/KDE/kdelibs/kio/jobclasses.moc:336
#17 0xb7e82530 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#18 0xb7e82c92 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#19 0xb76f8c79 in KIO::SlaveInterface::finished (this=0x876a7b0)
    at /home/kde-devel/kde/build/KDE/kdelibs/kio/slaveinterface.moc:161
#20 0xb76fa9f4 in KIO::SlaveInterface::dispatch (this=0x876a7b0, _cmd=104, 
    rawdata=@0xbfe380a4)
    at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/slaveinterface.cpp:175
#21 0xb76fb581 in KIO::SlaveInterface::dispatch (this=0x876a7b0)
    at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/slaveinterface.cpp:90
#22 0xb76ed4ce in KIO::Slave::gotInput (this=0x876a7b0)
    at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/slave.cpp:319
#23 0xb76ee93c in KIO::Slave::qt_metacall (this=0x876a7b0, 
    _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbfe38198)
    at /home/kde-devel/kde/build/KDE/kdelibs/kio/slave.moc:75
#24 0xb7e82530 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#25 0xb7e82c92 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#26 0xb7618c33 in KIO::Connection::readyRead (this=0x8677ed8)
    at /home/kde-devel/kde/build/KDE/kdelibs/kio/connection.moc:84
#27 0xb7619c21 in KIO::ConnectionPrivate::dequeue (this=0x8760488)
    at /home/kde-devel/kde/src/KDE/kdelibs/kio/kio/connection.cpp:82
#28 0xb761ab43 in KIO::Connection::qt_metacall (this=0x8677ed8, 
    _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0x8c341d8)
    at /home/kde-devel/kde/build/KDE/kdelibs/kio/connection.moc:72
#29 0xb7e7c249 in QMetaCallEvent::placeMetaCall ()
   from /usr/lib/qt4/libQtCore.so.4
#30 0xb7e7e309 in QObject::event () from /usr/lib/qt4/libQtCore.so.4
#31 0xb6be98a4 in QApplicationPrivate::notify_helper ()
   from /usr/lib/qt4/libQtGui.so.4
#32 0xb6beda75 in QApplication::notify () from /usr/lib/qt4/libQtGui.so.4
#33 0xb7998be6 in KApplication::notify (this=0xbfe3893c, receiver=0x8677ed8, 
    event=0x862bea8)
    at /home/kde-devel/kde/src/KDE/kdelibs/kdeui/kernel/kapplication.cpp:311
#34 0xb7e6cd59 in QCoreApplication::notifyInternal ()
   from /usr/lib/qt4/libQtCore.so.4
#35 0xb7e6e006 in QCoreApplicationPrivate::sendPostedEvents ()
   from /usr/lib/qt4/libQtCore.so.4
#36 0xb7e6e35d in QCoreApplication::sendPostedEvents ()
   from /usr/lib/qt4/libQtCore.so.4
#37 0xb6c79d7e in ?? () from /usr/lib/qt4/libQtGui.so.4
#38 0xb7e6c0d3 in QEventLoop::processEvents ()
   from /usr/lib/qt4/libQtCore.so.4
#39 0xb7e6c246 in QEventLoop::exec () from /usr/lib/qt4/libQtCore.so.4
#40 0xb7e6e401 in QCoreApplication::exec () from /usr/lib/qt4/libQtCore.so.4
#41 0xb6be923f in QApplication::exec () from /usr/lib/qt4/libQtGui.so.4
#42 0x0804b2d9 in main (argc=134573192, argv=0x80560e8)
    at /home/kde-devel/kde/src/KDE/kdepim/kontact/src/main.cpp:174
#0  0xb7f5c410 in __kernel_vsyscall ()