WRONG?

	function __construct($name, $title = null, $source = array(), $value = '', $form = null, $emptyString = true) {
		parent::__construct($name, $title, $source, $value, $form, $emptyString);

		$blogs = DB::query("SELECT ID, Title FROM SiteTree WHERE ID IN(SELECT DISTINCT ParentID FROM SiteTree WHERE ClassName='BlogEntry')")->map();
		$this->setSource($blogs);
	}

----------------

RIGHT?

	function __construct($name, $title = null, $source = array(), $value = '', $form = null, $emptyString = null) {

		if($emptyString) $this->setHasEmptyDefault(true);
		if(is_string($emptyString)) $this->setEmptyString($emptyString);

		parent::__construct($name, $title, $source, $value, $form, $emptyString);

		$blogs = DB::query("SELECT ID, Title FROM SiteTree WHERE ID IN(SELECT DISTINCT ParentID FROM SiteTree WHERE ClassName='BlogEntry')")->map();
		$this->setSource($blogs);
	}