Как сделать pop-up Combobox по позиции курсора в Memo?

Code:

unit CBoxInMemo;

interface

uses

Windows, Classes, Controls, Graphics, Forms, StdCtrls;

type

TFrmCboxInMemo = class(TForm)

   Button1: TButton;

   Memo1: TMemo;

   Label1: TLabel;

   ComboBox1: TComboBox;

   procedure Button1Click(Sender: TObject);

   procedure ComboBox1Exit(Sender: TObject);

   procedure ComboBox1Click(Sender: TObject);

private

   { Private declarations }

public

   { Public declarations }

end;

var

FrmCboxInMemo: TFrmCboxInMemo;

implementation

{$R *.DFM}

procedure TFrmCboxInMemo.Button1Click(Sender: TObject);

var

clientPos: TPoint;

lineHeight: Integer;

tmpFont: TFont;

begin

GetCaretPos(clientPos);

{Use the following calculation of line height only if you want your combobox

to appear below the char position you are referencing.}

tmpFont := Canvas.Font;

Canvas.Font := Memo1.Font;

lineHeight := Canvas.TextHeight('Xy');

Canvas.Font := tmpFont;

with ComboBox1 do

begin

   {Adjustment of Top by lineHeight only necessary if combobox is to appear below line.}

   Top := clientPos.Y + Memo1.Top + lineHeight;

   Left := clientPos.X + Memo1.Left;

   Visible := true;

   SetFocus;

end;

end;

procedure TFrmCboxInMemo.ComboBox1Exit(Sender: TObject);

begin

ComboBox1.Visible := false;

end;

procedure TFrmCboxInMemo.ComboBox1Click(Sender: TObject);

begin

ComboBox1.Visible := false;

end;

end.