Fix incorrect ownership

src/FactSystem/Fact.cc

@@ -701,7 +701,6 @@ FactValueSliderListModel* Fact::valueSliderModel(void)
 {
     if (!_valueSliderModel) {
         _valueSliderModel = new FactValueSliderListModel(*this);
-        QQmlEngine::setObjectOwnership(_valueSliderModel, QQmlEngine::JavaScriptOwnership);
     }
     return _valueSliderModel;
 }

src/FactSystem/FactValueSliderListModel.cc

@@ -30,6 +30,7 @@ FactValueSliderListModel::FactValueSliderListModel(Fact& fact, QObject* parent)
     , _initialValueRounded      (0)
     , _increment                (0)
 {
+    QQmlEngine::setObjectOwnership(this, QQmlEngine::CppOwnership);
 }
 
 FactValueSliderListModel::~FactValueSliderListModel()