unable to use targetElement within ui.facet when extending a standard cds view

[George_ki]

Hi, 
I tried to extend the ui.facet of a standard cds view with a new metadata extension. The purpose is to extend the object page of a fiori element app with a new section and present it as table (type: #LINEITEM_REFERENCE). First I extended the standard app with a new association to my ZCDSView which it has also a metadata extension file with annotation (@UI.LINEITEM).
I did also a metadata extension to the standard app on the customer layer and add a new label to the UI.facet as follow:
@ui.facet: [

{

id: 'addr',
label: 'address',
pupose: #standard,
type: #LINEITEM_REFERENCE,
position: 230,
targetElement: '_ZCDSView'                //defined as an alias of the association in the extension of the standard cds

}]

The problem is that The section 'address' is not appearing at all in the object page. But when removing the targetElement: '_ZCDSView',  the label appear with empty content.

I am also sure that the association has been defined properly in the extended view because the association can be followed in the data preview mode.
Any solution to this problem?

[junwu]

show me how you extend the cds with new association, did you expose the association?

[George_ki]

@AbapCatalog.sqlViewAppendName: 'CEXTADDRESS'
@EndUserText.label: 'Extension view'

extend view C_DFS_PositionHeaderTP with c_ext_address
association [1..*] to C_ZADDRESSVIEWTP as _ViewAddressTP on $projction.dfspositionId = _ViewAddressTP.DfsObjid

{
@ui.hidden: true
DfsPositionId as poshead, // no need to this element, just to silence the compilator
_ViewAddressTP
}

[George_ki]

the alias _ViewAddressTP is used as described above in targetElement in the metadata extension for the standard cds