[fw-mvc] Spurious at start of form

In the source HTML of my form I'm getting an unwanted </br> tag as the very
first thing output.

The start of my form __construct method is:

class ExtensioneditForm extends Zend_Form
{
public function __construct($options = null)
{ parent::__construct($options);
$this->setName('extensionedit');
$this->setDecorators(array('FormElements', array('HtmlTag', array('tag'
=> 'table')),'Form'));
...

Where is this suprious </br> coming from ? (and how do I get rid of it ?)

Thanks,

GTG