[icWasya]

только лучше так

Код:

procedure TForm1.ComboBox_Change(Sender: TObject);
var m:integer;
begin
for m:=0 to ComponentCount-1  do
begin
  if Components[m] = Sender then 
    continue;// защита от рекурсии
  if (Components[m] is TComboBox) then
     (Components[m] as TComboBox).ItemIndex:=(Sender as TComboBox).ItemIndex;
end;