bug is in your wip release (don't know if ealier versions also have this issue)
echo CHtml::tag($this->tagName, $this->htmlOptions); should be echo CHtml::opentag($this->tagName, $this->htmlOptions);
in init() because at run() you close the tag. with ::tag you open "and" close the tag. Therefore it happens on e.g. ie8 if you update your page with ajax and use a navbar with collapse = true you will get a wrong html code and therefore content will disapear.