prøv det her. Det virker på min. Du skal muligvis have XPmanifest sat på dit program
procedure TForm5.Button1Click(Sender: TObject);
const PBM_SETMARQUEE = WM_USER+10;
PBS_MARQUEE = $08;
var style: cardinal;
begin
style := GetWindowLong(ProgressBar1.Handle, GWL_STYLE);
style := style or PBS_MARQUEE;
SetWindowLong(ProgressBar1.Handle, GWL_STYLE, style);
SendMessage(ProgressBar1.Handle, PBM_SETMARQUEE, integer(true), lparam(100));
end;