QQuickWidget Crash.. i don`t know reason

Qt.Jo.Ha

Qt5Qml!QV4::ExecutionContext::simpleCall
Qt5Qml!QQmlJavaScriptExpression::evaluate
Qt5Qml!QQmlBinding::create
Qt5Qml!QQmlBinding::update
Qt5Qml!QQmlNotifier::emitNotify
Qt5Qml!QQmlData::signalEmitted
Qt5Core!QMetaObject::activate
Qt5Qml!QV4::QObjectMethod::methodIndex
Qt5Qml!QQmlDelegateModel::_q_itemsChanged
Qt5Qml!QQmlDelegateModel::_q_dataChanged
Qt5Qml!QQmlDelegateModel::qt_metacall
Qt5Core!QMetaObject::activate
Qt5Core!QAbstractItemModel::dataChanged
qtquickcontrolsplugin!None
Qt5Qml!QQmlPropertyPrivate::writeEnumProperty
Qt5Qml!QQmlPropertyPrivate::write
Qt5Qml!QQmlPropertyPrivate::writeValueProperty
Qt5Qml!QQmlBinding::slowWrite
Qt5Qml!QQmlBinding::update
Qt5Qml!QQmlBinding::create
Qt5Qml!QQmlBinding::update
Qt5Qml!QQmlNotifier::emitNotify
Qt5Qml!QQmlData::signalEmitted
Qt5Core!QMetaObject::activate
Qt5Qml!QQmlVMEMetaObject::metaCall
Qt5Core!QMetaProperty::write
Qt5Core!QObject::setProperty

i use custom calendar .. I don't know why it crashes. if you want more information ,request to me