type
  myGrid = class(TCustomGrid)
  end;

type
  myInplaceEditList = class(TInplaceEditList)
  end;

 

procedure TDemoForm.gdDemoGridCellClick(Column: TColumn);
begin
      Column.Field.FocusControl;
      Column.DropDownRows := ;
      myInplaceEditList(myGrid(grdColorSize).InplaceEditor).DropDown;
end;