Popupmenu -
procedure TForm1.EditPolylinePoints1Click(Sender: TObject);
begin
  { edit polyline points }
  ImageEnVect1.MouseInteractVt := [miEditPolyLine];
end;

Popupmenu -
procedure TForm1.AddPoint1Click(Sender: TObject);
var
  iPoint: TPoint;
begin
  iPoint := ScreenToClient(Mouse.CursorPos);
  ImageEnVect1.AddSelPoint(iPoint.X, iPoint.Y);
  ImageEnVect1.Update;
  // point is not added? 
end;

Popupmenu -
procedure TForm1.DeletePoint1Click(Sender: TObject);
begin
  ImageEnVect1.DelLastSelPoint;
  ImageEnVect1.Update;
  // point is not deleted?
end;