private
    { Private declarations }
    CodeList : TListBox;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.CodeListClick(Sender: TObject);
Var
  CurLine : Integer;
begin
  if CodeList.ItemIndex <> -1 then
  begin
    CurLine := Editor.CaretPos.Y;
    Editor.Lines[CurLine] := Editor.Lines[CurLine] + CodeList.Items[CodeList.ItemIndex];
  end;
  CodeList.Visible := False;
  Editor.SetFocus;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  CodeList := TListBox.Create(Self);
  CodeList.Parent := Editor;
  CodeList.Visible := False;
  CodeList.Width := 200;
  CodeList.Height := 100;
  CodeList.Items.Add('Caption');
  CodeList.Items.Add('Top');
  CodeList.Items.Add('Left');
  CodeList.OnClick := CodeListClick;
  CodeList.OnKeyDown := CodeListKeyDown;
end;

procedure TForm1.CodeListKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
Var
  CurLine : Integer;
begin
  case Key of
  13 : begin
         if CodeList.ItemIndex <> -1 then
         begin
           CurLine := Editor.CaretPos.Y;
           Editor.Lines[CurLine] := Editor.Lines[CurLine] + CodeList.Items[CodeList.ItemIndex];
         end;
       end;
  end;
  CodeList.Visible := False;
  Editor.SetFocus;
end;

procedure TForm1.EditorKeyPress(Sender: TObject; var Key: Char);
Var
  CliPos : TPoint;
  ListX, ListY : Integer;
begin
  if Key = '.' then
  begin
    GetCaretPos(CliPos);
    ListX := CliPos.X;
    ListY := CliPos.Y + CodeList.Canvas.TextHeight('W') + 4;
    if ListX + CodeList.Width >= Editor.Width then
      ListX := Editor.Width - CodeList.Width - 20;
    if ListY + CodeList.Height >= Editor.Height then
      ListY := Editor.Height - CodeList.Height - 20;
    with CodeList do
    Begin
      Top := ListY;
      Left := ListX;
      ItemIndex := 0;
      Visible := True;
      SetFocus;
    end;
  end
  else
    CodeList.Visible := False;
end;

end.