title: compute dynamically the allowDelete property of file download xpages
body: <p>I am using a file download control and I would like to set the value of the "allowDelete" property dynamically depending on whether the document is in edit or read mode. However, this
  property is computed onload of the page. I tried calling the function "setAllowDelete(boolean)" on the onclick event of a button or the "beforeRenderResponse" event of a custom control and a partial or full update to change the value of the property, but it didn't change.</p>
  
  <p>Do you know if there is a way to do this?</p>
  
  <p>Thanks a lot in advance!</p>