Application that crashed: kmail
Version of the application: 1.12.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-19-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
Do a search on a folder.

In the main Kmail window change to another folder.

Go back to search window and click on a mail found in search causes crash.

 -- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
The current source language is "auto; currently c".
[KCrash Handler]
#5  QString (this=0x21c4ef0, s=..., number=false) at ../../include/QtCore/../../src/corelib/tools/qstring.h:711
#6  QTextStreamPrivate::putString (this=0x21c4ef0, s=..., number=false) at io/qtextstream.cpp:933
#7  0x00007f476f326b56 in QTextStream::operator<< (this=0x2383120, string=...) at io/qtextstream.cpp:2511
#8  0x00007f4770aaf790 in QDebug::operator<< (this=0x12fb620, it=0x0) at /usr/include/qt4/QtCore/qdebug.h:108
#9  KMail::MessageListView::Core::View::setCurrentMessageItem (this=0x12fb620, it=0x0) at ../../kmail/messagelistview/core/view.cpp:768
#10 0x00007f4770a5f5fc in KMail::MessageListView::Widget::activateMessageItemByMsgBase (this=0x13a9280, msg=0x2a802f0) at ../../kmail/messagelistview/widget.cpp:276
#11 0x00007f477088251f in KMail::SearchWindow::slotShowMsg (this=0x22a3360, item=<value optimized out>) at ../../kmail/searchwindow.cpp:726
#12 0x00007f47708829b6 in KMail::SearchWindow::qt_metacall (this=0x22a3360, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffdac9f830) at ./searchwindow.moc:128
#13 0x00007f476f390ddc in QMetaObject::activate (sender=0x22e7a00, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x1) at kernel/qobject.cpp:3113
#14 0x00007f476fd55020 in QTreeWidget::itemClicked (this=0x21c4ef0, _t1=0x24013e0, _t2=1) at .moc/release-shared/moc_qtreewidget.cpp:201
#15 0x00007f476fd61028 in QTreeWidget::qt_metacall (this=0x22e7a00, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffdac9f9a0) at .moc/release-shared/moc_qtreewidget.cpp:144
#16 0x00007f4770881010 in KMail::MatchListView::qt_metacall (this=0x21c4ef0, _c=88, _id=0, _a=0x1) at ./searchwindow.moc:203
#17 0x00007f476f390ddc in QMetaObject::activate (sender=0x22e7a00, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x1) at kernel/qobject.cpp:3113
#18 0x00007f476fcdbc35 in QAbstractItemView::clicked (this=0x21c4ef0, _t1=<value optimized out>) at .moc/release-shared/moc_qabstractitemview.cpp:321
#19 0x00007f476fce8e8b in QAbstractItemView::mouseReleaseEvent (this=0x22e7a00, event=0x7fffdaca0640) at itemviews/qabstractitemview.cpp:1660
#20 0x00007f476f85d9c0 in QWidget::event (this=0x22e7a00, event=0x7fffdaca0640) at kernel/qwidget.cpp:7549
#21 0x00007f476fbb92a6 in QFrame::event (this=0x22e7a00, e=0x7fffdaca0640) at widgets/qframe.cpp:559
#22 0x00007f476fcec21b in QAbstractItemView::viewportEvent (this=0x22e7a00, event=0x7fffdaca0640) at itemviews/qabstractitemview.cpp:1476
#23 0x00007f476fd23420 in QTreeView::viewportEvent (this=0x22e7a00, event=0x7fffdaca0640) at itemviews/qtreeview.cpp:1266
#24 0x00007f476f37af47 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<value optimized out>, receiver=0x22d7ac0, event=0x7fffdaca0640) at kernel/qcoreapplication.cpp:726
#25 0x00007f476f80eecc in QApplicationPrivate::notify_helper (this=0xd67a40, receiver=0x22d7ac0, e=0x7fffdaca0640) at kernel/qapplication.cpp:4052
#26 0x00007f476f816011 in QApplication::notify (this=<value optimized out>, receiver=0x22d7ac0, e=0x7fffdaca0640) at kernel/qapplication.cpp:3758
#27 0x00007f47715d1ab6 in KApplication::notify (this=0x7fffdaca2670, receiver=0x22d7ac0, event=0x7fffdaca0640) at ../../kdeui/kernel/kapplication.cpp:302
#28 0x00007f476f37bc2c in QCoreApplication::notifyInternal (this=0x7fffdaca2670, receiver=0x22d7ac0, event=0x7fffdaca0640) at kernel/qcoreapplication.cpp:610
#29 0x00007f476f8158e0 in QCoreApplication::sendSpontaneousEvent (receiver=0x22d7ac0, event=0x7fffdaca0640, alienWidget=0x22d7ac0, nativeWidget=0x22a3360, buttonDown=<value optimized out>, 
    lastMouseReceiver=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#30 QApplicationPrivate::sendMouseEvent (receiver=0x22d7ac0, event=0x7fffdaca0640, alienWidget=0x22d7ac0, nativeWidget=0x22a3360, buttonDown=<value optimized out>, 
    lastMouseReceiver=<value optimized out>) at kernel/qapplication.cpp:2924
#31 0x00007f476f87ba0e in QETWidget::translateMouseEvent (this=0x22a3360, event=<value optimized out>) at kernel/qapplication_x11.cpp:4409
#32 0x00007f476f87aaa9 in QApplication::x11ProcessEvent (this=<value optimized out>, event=0x7fffdaca2170) at kernel/qapplication_x11.cpp:3550
#33 0x00007f476f8a3d0c in x11EventSourceDispatch (s=<value optimized out>, callback=<value optimized out>, user_data=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:146
#34 0x00007f4766614bce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#35 0x00007f4766618598 in ?? () from /lib/libglib-2.0.so.0
#36 0x00007f47666186c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#37 0x00007f476f3a41a6 in QEventDispatcherGlib::processEvents (this=0xd33930, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#38 0x00007f476f8a34be in QGuiEventDispatcherGlib::processEvents (this=0x21c4ef0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#39 0x00007f476f37a532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#40 0x00007f476f37a904 in QEventLoop::exec (this=0x7fffdaca24a0, flags=) at kernel/qeventloop.cpp:201
#41 0x00007f476f37cab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#42 0x0000000000402fe9 in main (argc=<value optimized out>, argv=<value optimized out>) at ../../kmail/main.cpp:146

Reported using DrKonqi