The assign field is not really intended to be "displayable". And your 
patch doesn't make sense because it shows a form field. If at all, it 
should show a table with assignments or something similar.

I am trying to use assign. I found that assign has no related display 
function. I simply add one in Horde/UI/VarRenderer/html.php:



     function _renderVarDisplay_assign(&$form, &$var, &$vars)

     {

         global $registry;



         Horde::addScriptFile('form_assign.js', 'horde', true);



         $name = $var->getVarName();

         $fname = $form->getName() . '.' . $name;

         $size = $var->type->getSize();

         $width = $var->type->getWidth();

         $lhdr = (bool) $var->type->getHeader(0);

         $rhdr = (bool) $var->type->getHeader(1);

         $this->_addOnLoadJavascript('Horde_Form_Assign.setField(\'' . 
$fname . '\');');



         $html = '<!--a75c305b1c0a6022--><table><tr><td>' .

              '<input type="hidden" name="' . $name . '__values" />' .

              sprintf('<select name="%s__left" multiple="multiple" 
size="%d" style="width:%s">',

                      $name, $size, $width

                      ) .

              $var->type->getOptions(0, $fname) .

              '</select></td><td>' .

              '</td><td>' .

              sprintf('<select name="%s__right" multiple="multiple" 
size="%d" style="width:%s">',

                      $name, $size, $width

                      ) .

              $var->type->getOptions(1, $fname) .

              '</select></td></tr></table>';



         return $html;

     }