Main contents (below menu bar) on page "Event details" don't show.

Apache throws a PHP Fatal error: Call to a member function setAttribute() on a non-object in /var/www/zabbix/include/classes/class.cuiwidget.php on line 98, referer: http://1.2.3.4/zabbixevents.php?sid=a43d3cd4365cec91&form_refresh=1&fullscreen=0&groupid=3&hostid=10073&source=0

When I comment out line 98 in class.cuiwidget.php, it works:
// $this->_footer->setAttribute('style', 'display: none;');

Looks like $this->_footer is not defined, maybe method setFooter() in same class never get's called for some reason?