How to position a TRichEdit control to a specific top index

Problem/Question/Abstract:

How does one position a Rich Edit control to a specific top index (e.g. Sendmessage(lbhandle, LB_SETTOPINDEX, 100, 0 works for list boxes, but is ignored by rich edits)?

Answer:

var
  firstline: Integer = 0;

procedure TForm1.Button2Click(Sender: TObject);
begin
  {record current first line}
  firstline := richedit1.perform(EM_GETFIRSTVISIBLELINE, 0, 0);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  {Scroll back to recorded position}
  with richedit1 do
    perform(em_linescroll, 0, firstline - perform(EM_GETFIRSTVISIBLELINE, 0, 0));
end;