public void OnSaveConvexShape()
{
_fd = new FileDialog();
_fd.Mode = FileDialog.ModeEnum.SaveFile;
_fd.AddFilter("*.tres, *.res ; Resource files");
_fd.Connect("file_selected", this, "OnConvexShapeSaveOK");
_fd.DialogHideOnOk = true;
AddChild(_fd);
_fd.PopupCentered(new Vector2(800, 600));
}