title: GWT - ListBox - pre-selecting an item
body: <p>I got a doubt regarding pre-selecting(<code>setSelectedIndex(index)</code>) an item in a ListBox, Im using Spring + GWT.</p>
  
  <p>I got a dialog that contains a panel, this panel has a FlexPanel, in which I've put a couple ListBox, this are filled up with data from my database.</p>
  
  <p>But this Panel is for updates of an entity in my database, thus I wanted it to pre-select the current properties for this items, allowing the user to change at will.</p>
  
  <p>I do the filling up in the update method of the widget.</p>
  
  <p>I tried setting the selectedItem in the update method, but it gives me an null error.</p>
  
  <p>I've searched a few places and it seems that the ListBox are only filled at the exact moment of the display. Thus pre-selecting would be impossible.</p>
  
  <p>I thought about some event, that is fired when the page is displayed.</p>
  
  <p>onLoad() doesnt work..</p>
  
  <p>Anyone have something to help me out in here?</p>