title: PrimeFaces f:setPropertyAction with dataTable works only after a row is selected
body: <p>Here is my Problem:</p>
  
  <ul>
  <li>Backing bean is <code>@SessionScoped</code></li>
  <li>I have a <code>p:dataTable</code> with <em>selectionMode</em> set to single and <em>selection</em> <code>#{bean.selectedCar}</code></li>
  <li>first column in the table is a commandLink that <em>updates</em> a dialog :detailDialog, <em>oncomplete</em> shows the dialog and has an <em>actionListener</em> that hast to clear some property in the bean</li>
  <li><code>f:setPropertyListener</code> has a value <code>#{item}</code> and target <code>#{bean.selectedCar}</code></li>
  </ul>
  
  <p>I want that the user is able to click the link and the dialog will display the information for the object on the row, but it works only if a row in the dataTable was selected first. If no row was selected and the user clicks on the commandLink NULL is passed to the <code>bean.selectedCar</code> and the page hangs.</p>
  
  <p>As a workaround I would like at least to be able to preselect the first row in the dataTable and hopefully this will do the trick.</p>