This is causing apps to segfault when calling Theme.loadTheme with this stack trace: 0 UCStyle::unbindItem(QQuickItem*) /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf1b8b65 1 ItemStyleAttached::setStyle(UCStyle*) /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf1993a3 2 ItemStyleAttached::qt_metacall(QMetaObject::Call, int, void**) /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf19af61 3 QMetaObject::metacall(QObject*, QMetaObject::Call, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e38750 4 QQmlPropertyPrivate::write(QObject*, QQmlPropertyData const&, QVariant const&, QQmlContextData*, QFlags) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7aba54a 5 QQmlPropertyPrivate::writeValueProperty(QObject*, QQmlPropertyData const&, QVariant const&, QQmlContextData*, QFlags) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7abb385 6 QQmlPropertyPrivate::writeBinding(QObject*, QQmlPropertyData const&, QQmlContextData*, QQmlJavaScriptExpression*, v8::Handle, bool, QFlags) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7abc537 7 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7be7767 8 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7be77e7 9 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7b5aa59 10 QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7b3bb05 11 QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7b3bad3 12 QQmlData::signalEmitted(QAbstractDeclarativeData*, QObject*, int, void**) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7aa3a79 13 QMetaObject::activate(QObject*, int, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e590f1 14 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e59d7b 15 ItemStyleAttached::styleChanged() /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf198835 16 ItemStyleAttachedPrivate::updateTheme() /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf1997ae 17 ItemStyleAttachedPrivate::_q_refreshStyle() /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf199e26 18 ?? /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf19a301 19 QMetaObject::activate(QObject*, int, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e59333 20 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e59d7b 21 ThemeEngine::themeChanged() /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf190f05 22 ThemeEnginePrivate::loadTheme(QUrl const&) /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf192574 23 ThemeEngine::loadTheme(QUrl const&) /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf1926b8 24 ?? /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf192a7f 25 ThemeEngine::qt_metacall(QMetaObject::Call, int, void**) /usr/lib/i386-linux-gnu/qt5/qml/Ubuntu/Components/libUbuntuComponents.so 0xaf192bec 26 QMetaObject::metacall(QObject*, QMetaObject::Call, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e38750 27 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7bd6b79 28 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7bd952e 29 QV8QObjectWrapper::Invoke(v8::Arguments const&) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7bd9e51 30 ?? /usr/lib/i386-linux-gnu/libQt5V8.so.5 0xb644e25d 31 ?? 0x3310a336 32 ?? 0x33126964 33 ?? 0x3310db41 34 ?? 0x3314348c 35 ?? 0x33121cb9 36 ?? 0x33112c8a 37 ?? /usr/lib/i386-linux-gnu/libQt5V8.so.5 0xb64783a5 38 ?? /usr/lib/i386-linux-gnu/libQt5V8.so.5 0xb6479ea8 39 ?? /usr/lib/i386-linux-gnu/libQt5V8.so.5 0xb6479fe9 40 v8::Function::Call(v8::Handle, int, v8::Handle*) /usr/lib/i386-linux-gnu/libQt5V8.so.5 0xb642256e 41 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7b5acdd 42 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7b5b290 43 QQmlBoundSignalExpression::evaluate(void**) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7af2b76 44 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7af3777 45 QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7b3bb05 46 QQmlData::signalEmitted(QAbstractDeclarativeData*, QObject*, int, void**) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7aa3a79 47 QMetaObject::activate(QObject*, int, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e590f1 48 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) /usr/lib/i386-linux-gnu/libQt5Core.so.5 0xb6e59d7b 49 ?? /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7c0f625 50 QQmlVME::complete(QQmlVME::Interrupt const&) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7aca830 51 QQmlComponentPrivate::complete(QQmlEnginePrivate*, QQmlComponentPrivate::ConstructionState*) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7abf460 52 QQmlComponentPrivate::completeCreate() /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7abf538 53 QQmlComponent::completeCreate() /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7abf5ce 54 QQmlComponent::create(QQmlContext*) /usr/lib/i386-linux-gnu/libQt5Qml.so.5 0xb7abf3cc 55 ?? 0x804b276 56 __libc_start_main libc-start.c 260 0xb6959935 57 ?? 0x804d66d