Thank you Helen for a reply.

> So the first thing to do will be to
> remove that TIBOTransaction and just go with the internal
> DefaultTransaction that is embedded in the IBODatabase.

Interesting idea, but nothin's changed.

I'll try to describe it again:
Have manually defined lookup field on TIBOQuery:

object IBOQueryDEPARTMENTNAME: TStringField
FieldKind = fkLookup
FieldName = 'DEPARTMENT'
LookupDataSet = IBOTable
LookupKeyFields = 'ID'
LookupResultField = 'NAME'
KeyFields = 'ID_DEPARTMENT'
Lookup = True
end

If i'll make a select with query, it will correctly return department
name based on: department id stored in a query and relational id in
open table, resulting the name of department.

If i'll make an edit of ID_DEPARTMENT in the query, than post and
commit, it will reflect changes: ID_DEPARTMENT-OK, but lookup field
returns empty string (related table is still open).

Tried to call some "RefreshLookupList" method of the field, but no
success.

Thank you for any hint.