title: how to unselect all options in multiselect widget
body: <p>I am using jquery multiselect widget. I would like to uncheck all if all them were checked manually. I have a sample code in 
  <a href="http://jsfiddle.net/fG6PT/8/">JSFiddle--> Code</a></p>
  
  <p>This doesn't work. When the select options are selected manually, check for no of unchecked options in select it gives me 1 (at the click of last option) the first time. so I checked if <code>$this.children("option").not('[selected]').length</code>  is 1 and  <code>ui.checked</code>  and calling the <code>uncheckAll</code>
  but after that it is behaving properly the code 
  if <code>$this.children("option").not('[selected]').length</code>  gives me 0 when selecting the final one.</p>
  
  <p>I am wondering what is happening.</p>