Version:            (using KDE 3.5.10)
OS:                Linux
Installed from:    SuSE RPMs

I have a reproduceable crash (segmentation fault) when switching from "Merged calendar" to "Calendars Side by Side" in kontact's korganizer. 
This DID work before, so I guess it's due to the update to kde-3.5.10. The system is an intel x86-64 running opensuse-10.2. 

Funny thing is: 
currently only two calendars defined: local birthdays and a local calendar. I had an additional calendar on an Exchange-IMAP4-Account when it did work weeks ago ?!?

The backtrace: 
(no debugging symbols found)
...
[Thread debugging using libthread_db enabled]
[New Thread 0x42003940 (LWP 19427)]
[New Thread 0x41802940 (LWP 19426)]
[New Thread 0x41001940 (LWP 19425)]
[New Thread 0x40800940 (LWP 19424)]
[KCrash handler]
#5  0x00002b94468a336d in KHolidays::getHolidays ()
   from /opt/kde3/lib64/libkholidays.so.1
#6  0x00002b9447b32592 in KOGlobals::isWorkDay ()
   from /opt/kde3/lib64/libkorganizer.so.1
#7  0x00002b9447a9dc10 in KOAgendaView::setHolidayMasks ()
   from /opt/kde3/lib64/libkorganizer.so.1
#8  0x00002b9447aa072d in KOAgendaView::fillAgenda ()
   from /opt/kde3/lib64/libkorganizer.so.1
#9  0x00002b9447aa11fc in KOAgendaView::showDates ()
   from /opt/kde3/lib64/libkorganizer.so.1
#10 0x00002b9447b6e8bc in KOrg::MultiAgendaView::showDates ()
   from /opt/kde3/lib64/libkorganizer.so.1
#11 0x00002b943e5807d3 in QWidgetStack::raiseWidget ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#12 0x00002b943e56e122 in QTabWidget::showTab ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#13 0x00002b943e75db9b in QTabWidget::qt_invoke ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#14 0x00002b943e46118c in QObject::activate_signal ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#15 0x00002b943e461844 in QObject::activate_signal ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#16 0x00002b943e56cef2 in QTabBar::setCurrentTab ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#17 0x00002b943e56a517 in QTabBar::mousePressEvent ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#18 0x00002b943e492e06 in QWidget::event ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#19 0x00002b943e56b1d5 in QTabBar::event ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#20 0x00002b943e40a9ed in QApplication::internalNotify ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#21 0x00002b943e40b902 in QApplication::notify ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#22 0x00002b943dbf1b2d in KApplication::notify ()
   from /opt/kde3/lib64/libkdecore.so.4
#23 0x00002b943e3b26e3 in QETWidget::translateMouseEvent ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#24 0x00002b943e3b1625 in QApplication::x11ProcessEvent ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#25 0x00002b943e3c09d2 in QEventLoop::processEvents ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#26 0x00002b943e41f263 in QEventLoop::enterLoop ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#27 0x00002b943e41f112 in QEventLoop::exec ()
   from /usr/lib/qt3/lib64/libqt-mt.so.3
#28 0x00000000004190e9 in ?? ()
#29 0x00002b943ee79ae4 in __libc_start_main () from /lib64/libc.so.6
#30 0x00000000004188a9 in ?? ()
#31 0x00007fff6f165d38 in ?? ()
#32 0x0000000000000000 in ?? ()