Version:           1.9 (using KDE 3.5 (RC1), Gentoo)
Compiler:          gcc version 3.3.6 (Gentoo 3.3.6, ssp-3.3.6-1.0, pie-8.7.8)
OS:                Linux (i686) release 2.6.11-gentoo-r11

It could be a duplicate of 82859, but that bug is marked as resolved, while I am still experiencing this with 3.5 rc1!

1. Open a composer window and type in something
2. Start spell checking and change language. A dialog appears saying "You have to restart the dialog for changes to take effect". Dismiss it.
3. Now, most of the time kmail crashes. Not always, however!

[Thread debugging using libthread_db enabled]
[New Thread 16384 (LWP 20847)]
[KCrash handler]
#5  0xb788b236 in QGVector::size () from /usr/kde/3.5/lib/libkhtml.so.4
#6  0xb5c4ae25 in QPtrVector<QConnectionList>::size ()
   from /usr/qt/3/lib/libqt-mt.so.3
#7  0xb5c4ae49 in QSignalVec::at () from /usr/qt/3/lib/libqt-mt.so.3
#8  0xb5c4665b in QObject::receivers () from /usr/qt/3/lib/libqt-mt.so.3
#9  0xb60418df in QListBox::selected () from /usr/qt/3/lib/libqt-mt.so.3
#10 0xb5d45ec4 in QListBox::mouseDoubleClickEvent ()
   from /usr/qt/3/lib/libqt-mt.so.3
#11 0xb5c8c08c in QWidget::event () from /usr/qt/3/lib/libqt-mt.so.3
#12 0xb5bd875d in QApplication::internalNotify ()
   from /usr/qt/3/lib/libqt-mt.so.3
#13 0xb5bd7c90 in QApplication::notify () from /usr/qt/3/lib/libqt-mt.so.3
#14 0xb6458dfb in KApplication::notify ()
   from /usr/kde/3.5/lib/libkdecore.so.4
#15 0xb779fbcd in QApplication::sendEvent ()
   from /usr/kde/3.5/lib/libkhtml.so.4
#16 0xb5d03732 in QComboBox::eventFilter () from /usr/qt/3/lib/libqt-mt.so.3
#17 0xb5c45ef2 in QObject::activate_filters ()
   from /usr/qt/3/lib/libqt-mt.so.3
#18 0xb5c45d6f in QObject::event () from /usr/qt/3/lib/libqt-mt.so.3
#19 0xb5c8bf7b in QWidget::event () from /usr/qt/3/lib/libqt-mt.so.3
#20 0xb5bd875d in QApplication::internalNotify ()
   from /usr/qt/3/lib/libqt-mt.so.3
#21 0xb5bd7c90 in QApplication::notify () from /usr/qt/3/lib/libqt-mt.so.3
#22 0xb6458dfb in KApplication::notify ()
   from /usr/kde/3.5/lib/libkdecore.so.4
#23 0xb5b5eb3e in QApplication::sendSpontaneousEvent ()
   from /usr/qt/3/lib/libqt-mt.so.3
#24 0xb5b563f2 in QETWidget::translateMouseEvent ()
   from /usr/qt/3/lib/libqt-mt.so.3
#25 0xb5b54148 in QApplication::x11ProcessEvent ()
   from /usr/qt/3/lib/libqt-mt.so.3
#26 0xb5b722fd in QEventLoop::processEvents ()
   from /usr/qt/3/lib/libqt-mt.so.3
#27 0xb5befd01 in QEventLoop::enterLoop () from /usr/qt/3/lib/libqt-mt.so.3
#28 0xb5befc1a in QEventLoop::exec () from /usr/qt/3/lib/libqt-mt.so.3
#29 0xb5bd88ff in QApplication::exec () from /usr/qt/3/lib/libqt-mt.so.3
#30 0x0804aad5 in ?? ()
#31 0xbffff1e0 in ?? ()
#32 0x00000000 in ?? ()
#33 0x00000000 in ?? ()
#34 0x00000000 in ?? ()
#35 0xb625b900 in vtable for QGArray () from /usr/qt/3/lib/libqt-mt.so.3
#36 0x081c6688 in ?? ()
#37 0xbffff108 in ?? ()
#38 0xb557828f in pthread_mutex_unlock () from /lib/libpthread.so.0
#39 0xb535856c in __libc_start_main () from /lib/libc.so.6
#40 0x0804a7a1 in ?? ()