procedure TMAINFORM.DataSetBroker1DataChange(Sender: TObject; Field: TDataField);
var lBookMark :String;
begin
if Field<>nil then
begin
if Field.FieldName='XZ' then
begin
DataSetBroker1.DataSet.DisableControls;
lBookMark := DataSetBroker1.DataSet.Bookmark;
DataSetBroker1.DataSet.First;
while not DataSetBroker1.DataSet.Eof do
begin
DataSetBroker1.DataSet.Next;
end;
DataSetBroker1.DataSet.Bookmark :=lBookMark;
DataSetBroker1.DataSet.EnableControls;