S/4 HANA 2021 Manage Specification app - which ID listing?

Dear all

I am struggling a bit with the app 'Manage Specifications' (F2213). It does not show any identifiers:

We don't have this kind of problem in other apps, e.g. 'Manage Real Substances; (F2477)

D_HITLIST should be maintained correctly . Could it be that the 'Manage Specification' is using a different identification listing?

Thanks & regards
Jan