Clearing Rows

Selected customer focused then it displays customer inv and if invoice has any inv items via use of search buttons.

Issue I wanted solve when newly added customer selected without any invoice to display. Inv Items tGrid was displaying all inv items of all customers.

The following sorted on cell click (when browsing customers tGrid with mouse)

procedure tgMainCustCellClick2; 
begin
  if Form1.tgMainCustomersTrans.rowcount = 0 then
  begin
  Form1.tgMainCustomersTransItems.clearrows;
  end;
end;

However, when browsing customer records with keyboard up and down keys following didn't work?

procedure tgMainCustKeyUp2;
begin
  if Form1.tgMainCustomersTrans.rowcount = 0 then
  begin
  Form1.tgMainCustomersTransItems.clearrows;
  end;
end;

Please see the attached sample project