* {@link Roo.bootstrap.DateField} and {@link Roo.bootstrap.ComboBox} are perfect examples of this.
* @cfg {String} triggerClass An additional CSS class used to style the trigger button. The trigger will always get the
* class 'x-form-trigger' by default and triggerClass will be <b>appended</b> if specified.
+ * @cfg {String} caret
+
* @constructor
* Create a new TriggerField.
* @param {Object} config Configuration options (valid {@Roo.bootstrap.Input} config options will also be applied