public ICommand CreateCommand()
        {
            ICommand ret = null;
            using (TextPromptDialog dlg = new TextPromptDialog("Add Marker", "Name", anchor, "&Add"))
            {
                if (dlg.ShowDialog() == DialogResult.OK)
                {
                    ret = new AddMarkerCommand(app, parent, dlg.UserText, "directional_marker.mesh");
                }
            }

            return ret;
        }
        public ICommand CreateCommand()
        {
            ICommand ret = null;

            using (TextPromptDialog dlg = new TextPromptDialog("Add Marker", "Name", anchor, "&Add"))
            {
                if (dlg.ShowDialog() == DialogResult.OK)
                {
                    ret = new AddMarkerCommand(app, parent, dlg.UserText, "directional_marker.mesh");
                }
            }

            return(ret);
        }