+++ This bug was initially created as a clone of Bug #179616 +++

Kontact crashing when I switch to calendar, journal and to-do list.  Crash is reproducible.
I'm using:
Qt: 4.4.3
KDE: 4.2.00 (KDE 4.2.0) "release 82.2"
Kontact: 1.4

Below is attached backtrace after while switching to calendar:
Application: Kontact (kontact), signal SIGSEGV
[Current thread is 1 (Thread 0xb493f920 (LWP 17054))]

Thread 3 (Thread 0xb0834b90 (LWP 17064)):
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xb65d3f62 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#2  0xb663384c in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/libQtCore.so.4
#3  0xb66289c6 in ?? () from /usr/lib/libQtCore.so.4
#4  0xb663285e in ?? () from /usr/lib/libQtCore.so.4
#5  0xb65d01b5 in start_thread () from /lib/libpthread.so.0
#6  0xb59e43be in clone () from /lib/libc.so.6

Thread 2 (Thread 0xaff3fb90 (LWP 17080)):
#0  0xffffe430 in __kernel_vsyscall ()
#1  0xb59dd411 in select () from /lib/libc.so.6
#2  0xb6701dc7 in ?? () from /usr/lib/libQtCore.so.4
#3  0xb663285e in ?? () from /usr/lib/libQtCore.so.4
#4  0xb65d01b5 in start_thread () from /lib/libpthread.so.0
#5  0xb59e43be in clone () from /lib/libc.so.6

Thread 1 (Thread 0xb493f920 (LWP 17054)):
[KCrash Handler]
#6  0xb663dff7 in QDate::isValid() const () from /usr/lib/libQtCore.so.4
#7  0xb690def3 in KDateTime::isValid() const () from /usr/lib/libkdecore.so.5
#8  0xb72cfda4 in KCal::Todo::dtDue(bool) const () from /usr/lib/libkcal.so.4
#9  0xb72cfe64 in KCal::Todo::isOverdue() const () from /usr/lib/libkcal.so.4
#10 0xaf5b7b30 in ?? () from /usr/lib/libkorganizerprivate.so.4
#11 0xb6202b9e in QSortFilterProxyModel::data(QModelIndex const&, int) const () from /usr/lib/libQtGui.so.4
#12 0xb6227432 in QStyledItemDelegate::initStyleOption(QStyleOptionViewItem*, QModelIndex const&) const () from /usr/lib/libQtGui.so.4
#13 0xb62282b4 in QStyledItemDelegate::sizeHint(QStyleOptionViewItem const&, QModelIndex const&) const () from /usr/lib/libQtGui.so.4
#14 0xaf5bf1e4 in ?? () from /usr/lib/libkorganizerprivate.so.4
#15 0xb61b99d9 in QTreeView::indexRowSizeHint(QModelIndex const&) const () from /usr/lib/libQtGui.so.4
#16 0xb61b9d52 in ?? () from /usr/lib/libQtGui.so.4
#17 0xb61ba010 in ?? () from /usr/lib/libQtGui.so.4
#18 0xb61ba392 in QTreeView::updateGeometries() () from /usr/lib/libQtGui.so.4
#19 0xb6179359 in QAbstractItemView::doItemsLayout() () from /usr/lib/libQtGui.so.4
#20 0xb61c5a2a in QTreeView::doItemsLayout() () from /usr/lib/libQtGui.so.4
#21 0xb6183bd1 in QAbstractItemView::timerEvent(QTimerEvent*) () from /usr/lib/libQtGui.so.4
#22 0xb61c480b in QTreeView::timerEvent(QTimerEvent*) () from /usr/lib/libQtGui.so.4
#23 0xb673204f in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#24 0xb5d0f104 in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#25 0xb6045a83 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4
#26 0xb60dcc8d in QAbstractScrollArea::event(QEvent*) () from /usr/lib/libQtGui.so.4
#27 0xb6179ebc in QAbstractItemView::event(QEvent*) () from /usr/lib/libQtGui.so.4
#28 0xb5cb78fc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#29 0xb5cbf82a in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#30 0xb6cc291d in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#31 0xb6722961 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#32 0xb6750b86 in ?? () from /usr/lib/libQtCore.so.4
#33 0xb674d060 in ?? () from /usr/lib/libQtCore.so.4
#34 0xb50ca9a8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0xb50ce063 in ?? () from /usr/lib/libglib-2.0.so.0
#36 0xb50ce221 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#37 0xb674cfb8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#38 0xb5d50785 in ?? () from /usr/lib/libQtGui.so.4
#39 0xb672101a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#40 0xb67211da in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#41 0xb6942251 in KJob::exec() () from /usr/lib/libkdecore.so.5
#42 0xaffaddc2 in ?? () from /usr/lib/kde4/kcal_akonadi.so
#43 0xaffb0406 in ?? () from /usr/lib/kde4/kcal_akonadi.so
#44 0xb73362ed in KCal::ResourceCalendar::load() () from /usr/lib/libkcal.so.4
#45 0xb73485d1 in KCal::CalendarResources::load() () from /usr/lib/libkcal.so.4
#46 0xaf73b913 in ?? () from /usr/lib/kde4/korganizerpart.so
#47 0xaf73c3e2 in QObject* KPluginFactory::createPartInstance<KOrganizerPart>(QWidget*, QObject*, QList<QVariant> const&) () from /usr/lib/kde4/korganizerpart.so
#48 0xb6a3f34f in KPluginFactory::create(char const*, QWidget*, QObject*, QList<QVariant> const&, QString const&) () from /usr/lib/libkdecore.so.5
#49 0xb7862c72 in Kontact::Core::createPart(char const*) () from /usr/lib/libkontactinterfaces.so.4
#50 0xb7864237 in Kontact::Plugin::loadPart() () from /usr/lib/libkontactinterfaces.so.4
#51 0xb197fbe5 in ?? () from /usr/lib/kde4/kontact_korganizerplugin.so
#52 0xb7864192 in Kontact::Plugin::part() () from /usr/lib/libkontactinterfaces.so.4
#53 0xb7883228 in Kontact::MainWindow::selectPlugin(Kontact::Plugin*) () from /usr/lib/libkontactprivate.so.4
#54 0xb78830b4 in Kontact::MainWindow::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkontactprivate.so.4
#55 0xb6737580 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#56 0xb6738302 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#57 0xb7885a23 in ?? () from /usr/lib/libkontactprivate.so.4
#58 0xb7885abf in ?? () from /usr/lib/libkontactprivate.so.4
#59 0xb7885d6a in ?? () from /usr/lib/libkontactprivate.so.4
#60 0xb6737580 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#61 0xb6738302 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#62 0xb7885e53 in ?? () from /usr/lib/libkontactprivate.so.4
#63 0xb78867fd in ?? () from /usr/lib/libkontactprivate.so.4
#64 0xb6737580 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#65 0xb6738302 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#66 0xb61ce779 in QItemSelectionModel::currentChanged(QModelIndex const&, QModelIndex const&) () from /usr/lib/libQtGui.so.4
#67 0xb61ce91d in QItemSelectionModel::setCurrentIndex(QModelIndex const&, QFlags<QItemSelectionModel::SelectionFlag>) () from /usr/lib/libQtGui.so.4
#68 0xb618093a in QAbstractItemView::mousePressEvent(QMouseEvent*) () from /usr/lib/libQtGui.so.4
#69 0xb5d0fa49 in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#70 0xb6045a83 in QFrame::event(QEvent*) () from /usr/lib/libQtGui.so.4
#71 0xb60dc1bf in QAbstractScrollArea::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4
#72 0xb6186f3f in QAbstractItemView::viewportEvent(QEvent*) () from /usr/lib/libQtGui.so.4
#73 0xb60de765 in ?? () from /usr/lib/libQtGui.so.4
#74 0xb6721b3a in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#75 0xb5cb78da in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#76 0xb5cc0111 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#77 0xb6cc291d in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#78 0xb6722961 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#79 0xb5cbf39e in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&) () from /usr/lib/libQtGui.so.4
#80 0xb5d29716 in ?? () from /usr/lib/libQtGui.so.4
#81 0xb5d28ac5 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#82 0xb5d5108a in ?? () from /usr/lib/libQtGui.so.4
#83 0xb50ca9a8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#84 0xb50ce063 in ?? () from /usr/lib/libglib-2.0.so.0
#85 0xb50ce221 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#86 0xb674cfb8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#87 0xb5d50785 in ?? () from /usr/lib/libQtGui.so.4
#88 0xb672101a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#89 0xb67211da in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#90 0xb6723895 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#91 0xb5cb7777 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#92 0x0804bf8f in _start ()