Jason, Helen,

Thanks for your input Helen.

What you describe is what I had expected to work. But it is not.

Upon further investigation, I traced the code back to the
TIBODataSet.pas

The code seems inconsistent with the BDE as the query is opened
before the parameter is set.

As in TIBODataSet.pas:

procedure TIBODataset.DoBeforeOpen;
begin
InternalDataset.SysOpen;
FCurRowNum := InternalDataset.BofRowNum;
InternalDataset.BufferRowNum := FCurRowNum;
inherited DoBeforeOpen;
end;

to work as per BDE:

procedure TIBODataset.DoBeforeOpen;

begin
// Insert Inherited here, inherited is calling event handler
inherited DoBeforeOpen;
InternalDataset.SysOpen;
FCurRowNum := InternalDataset.BofRowNum;
InternalDataset.BufferRowNum := FCurRowNum;
end;

Thanks,

John