Author: Jonas Bilinkevicius

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:

1   var
2     firstline: Integer = 0;
3   
4   procedure TForm1.Button2Click(Sender: TObject);
5   begin
6     {record current first line}
7     firstline := richedit1.perform(EM_GETFIRSTVISIBLELINE, 0, 0);
8   end;
9   
10  procedure TForm1.Button3Click(Sender: TObject);
11  begin
12    {Scroll back to recorded position}
13    with richedit1 do
14      perform(em_linescroll, 0, firstline - perform(EM_GETFIRSTVISIBLELINE, 0, 0));
15  end;