/// new attributes should be added to end of the feature in order to provide
/// correct attribute values in previous saved studies
data()->addAttribute(LENGTH_ID(), ModelAPI_AttributeDouble::typeId());
+
+ data()->addAttribute(PARENT_ID(), ModelAPI_AttributeReference::typeId());
+ ModelAPI_Session::get()->validators()->registerNotObligatory(getKind(), PARENT_ID());
}
void SketchPlugin_Line::initDerivedClassAttributes()