code: function _iniBtnWrapper() {
  		var $wrapper = gearbox.dom.$body || gearbox.dom.$root
  		$wrapper.on('click', function (ev) {
  			var $target = gearbox.$(ev.target)
  			if ($target.hasClass(CLS_BTN_WRAPPER) && !$target.hasClass(CLS_BTN_DISABLED)) {
  				var $btnWrapper = $target
  				var selBtn = ([].concat('.' + CLS_BTN, BTN_ELEM_TAGS)).join(', ')
  				var $btn = $btnWrapper.find(selBtn).first()
  				if (!$btn.hasClass(CLS_BTN_DISABLED)) {
  					$btn.trigger('click')
  				}
  			}
  		})
  	}
docs: util 
  if click on a btn wrapper, trigger `click` event on the btn inside of the wrapper
  @private