Application that crashed: kate
Version of the application: 3.3.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-21-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
In Kate, I am using a custom template to allow folding for plaintext files (see below). Usually, this works fine. 

After pressing CTRL-Shift-Minus to collapse the top-level, I briefly saw the text collapse, and then Kate crashed.

This is the custom template used:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE language SYSTEM "language.dtd">
<language name="Text with folding" section="" version="1.00" kateversion="2.3" extensions="*.txt" mimetype="" author="" license="">
  <highlighting>
    <contexts>
      <context name="Normal" attribute="Normal Text" lineEndContext="#stay"/>
    </contexts>
    <itemDatas>
      <itemData name="Normal Text" defStyleNum="dsNormal"/>
    </itemDatas>
  </highlighting>
  <general>
    <folding indentationsensitive="1" />
  </general>
</language> 


 -- Backtrace:
Application: Kate (kdeinit4), signal: Segmentation fault
[KCrash Handler]
#5  0x00007f3ef404a5d8 in ?? () from /usr/lib/kde4/katepart.so
#6  0x00007f3ef404761e in ?? () from /usr/lib/kde4/katepart.so
#7  0x00007f3ef4094bf0 in ?? () from /usr/lib/kde4/katepart.so
#8  0x00007f3ef409cc2f in ?? () from /usr/lib/kde4/katepart.so
#9  0x00007f3ef408728d in ?? () from /usr/lib/kde4/katepart.so
#10 0x00007f3f02ca3ddc in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#11 0x00007f3f00c390a7 in QAction::triggered(bool) () from /usr/lib/libQtGui.so.4
#12 0x00007f3f00c3a4ef in QAction::activate(QAction::ActionEvent) () from /usr/lib/libQtGui.so.4
#13 0x00007f3f00c3cfa7 in QAction::event(QEvent*) () from /usr/lib/libQtGui.so.4
#14 0x00007f3f017a417d in KAction::event(QEvent*) () from /usr/lib/libkdeui.so.5
#15 0x00007f3f00c3eefc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#16 0x00007f3f00c461ce in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#17 0x00007f3f01875ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#18 0x00007f3f02c8ec2c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#19 0x00007f3f00c73666 in ?? () from /usr/lib/libQtGui.so.4
#20 0x00007f3f00c754f7 in ?? () from /usr/lib/libQtGui.so.4
#21 0x00007f3f00c46e6e in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#22 0x00007f3f01875ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#23 0x00007f3f02c8ec2c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#24 0x00007f3f00ccfdfa in ?? () from /usr/lib/libQtGui.so.4
#25 0x00007f3f00cd2370 in ?? () from /usr/lib/libQtGui.so.4
#26 0x00007f3f00caa493 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#27 0x00007f3f00cd3d0c in ?? () from /usr/lib/libQtGui.so.4
#28 0x00007f3effb6fbce in g_main_dispatch (context=0x12acdb0) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:1960
#29 IA__g_main_context_dispatch (context=0x12acdb0) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2513
#30 0x00007f3effb73598 in g_main_context_iterate (context=0x12acdb0, block=<value optimized out>, dispatch=<value optimized out>, self=<value optimized out>)
    at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2591
#31 0x00007f3effb736c0 in IA__g_main_context_iteration (context=0x12acdb0, may_block=1) at /build/buildd/glib2.0-2.22.3/glib/gmain.c:2654
#32 0x00007f3f02cb71a6 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#33 0x00007f3f00cd34be in ?? () from /usr/lib/libQtGui.so.4
#34 0x00007f3f02c8d532 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#35 0x00007f3f02c8d904 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#36 0x00007f3f02c8fab9 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#37 0x00007f3ef7054d2d in kdemain () from /usr/lib/libkdeinit4_kate.so
#38 0x0000000000406da8 in _start ()

Reported using DrKonqi