hello Harvey,

maybe you can use an AfterScroll event for your query:

begin
MyLookupCombo.Enabled := MyQuery.FieldByName('RELEVANT').AsBoolean
end;

Remember that to use the AsBoolean property you have to define that field as
Boolean in the ColumnAttributes property of the query:

RELEVANT=BOOLEAN

or, if you want to specify also the Boolean values the field can assume:

RELEVANT=BOOLEAN=1;0

or

RELEVANT=BOOLEAN=T;F

or whatever... The True value is the first.

HTH
Salvatore