Hi, when i define a description based on this code : ^ (MAToOneRelationDescription new) componentClass: MAInternalEditorComponent ; classes: (Array with: MAIndirizzoModel); autoAccessor: 'indirizzoMemo'; label: 'Indirizzo'; comment: 'Indirizzo di riferimento'; priority: 220; beReadonly; yourself where i set beReadonly. A) I found error when display it into: renderViewerOn: html html render: (self component readonly: self isReadonly; yourself) because self component answer nil. B) Another problem is relative to the same description when i rendering it as subComponent but with beReadonly setting. When i do "Save" the container erase errors relative to this subcomponent descriptions . But it's readOnly and d'ont do any control on it. C) I'm interested to incorporate the subComponent at the first level ( without the create buttons ) I create a MAInternalEditorComponent subclass: #MAOneToOneDirectComponent and change the : buildComponent "create new default value for directly rendering the subcomponent without button " self value isNil ifTrue:[ self value: self selected new. component := nil ]. ^ self value isNil ifFalse: [ (self description reference asComponentOn: self value) setParent: super; yourself ] It work fine. But the rendering is with to level the master and the slave. I can incorporate the slave description at first level ? Thanks for any considerations. Dario