dat.gui/elements/controller-string/controller-string.js

Gui.register('controller-string', function(value) {

  return typeof value == 'string';

});

Polymer('controller-string', {

  click: function(e) {

    this.$.input.select();

  },

  keydown: function(e) {

    if (e.keyCode == 13) {
      this.$.input.blur();
    }

  }

});