Crash when opening QtQuick Controls ComboBox

[Michael Sheldon]

Although QtQuick Controls aren't installed by default on the device they may be packaged with click applications (such as GCompris). Currently the ComboBox component from QtQuick Controls exposes a crash in unity8.

Steps to reproduce:

1) Install qml-module-qtquick-controls

 2) Run the following QML:

import QtQuick 2.2
import QtQuick.Controls 1.2

ApplicationWindow {

    ComboBox {

    }

}

 3) Tap the combo box

Expected output:

 ComboBox should open

Actual output:

 Unity switches back to the dash and then crashes with a segmentation fault (the application itself continues running)

Backtrace:

Program terminated with signal SIGSEGV, Segmentation fault.
#0 0xaadd1344 in qtmir::MirSurfaceItem::updateMirSurfaceFocus(bool) ()
   from /usr/lib/arm-linux-gnueabihf/qt5/qml/Unity/Application/libunityapplicationplugin.so
(gdb) bt
#0 0xaadd1344 in qtmir::MirSurfaceItem::updateMirSurfaceFocus(bool) ()
   from /usr/lib/arm-linux-gnueabihf/qt5/qml/Unity/Application/libunityapplicationplugin.so
#1 0xb64e671e in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/arm-linux-gnueabihf/libQt5Core.so.5
#2 0xb6876cd8 in QQuickItem::activeFocusChanged(bool) () from /usr/lib/arm-linux-gnueabihf/libQt5Quick.so.5
#3 0xb688618e in QQuickWindowPrivate::notifyFocusChangesRecur(QQuickItem**, int) () from /usr/lib/arm-linux-gnueabihf/libQt5Quick.so.5
#4 0xb688b170 in QQuickWindowPrivate::setFocusInScope(QQuickItem*, QQuickItem*, Qt::FocusReason, QFlags<QQuickWindowPrivate::FocusOption>) ()
   from /usr/lib/arm-linux-gnueabihf/libQt5Quick.so.5
#5 0xb687a802 in QQuickItem::setFocus(bool, Qt::FocusReason) () from /usr/lib/arm-linux-gnueabihf/libQt5Quick.so.5
#6 0xb6882a78 in QQuickItem::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/arm-linux-gnueabihf/libQt5Quick.so.5
#7 0xb6b3fe40 in QQmlVMEMetaObject::metaCall(QMetaObject::Call, int, void**) () from /usr/lib/arm-linux-gnueabihf/libQt5Qml.so.5
#8 0xbeb90720 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

[Albert Astals Cid (aacid)]

Can confirm the crash, looks more qtmir than unity8, but can be both, i tried with lp:~gerboland/qtmir/multiple-windows-per-app as Gerry suggested but what that made things work less than more.