header not rendered for components whithin enclosure in ajax response

Ajax response doesn't contain the binding of events (Wicket.Ajax.ajax({"u":...) of components while they are positionned within an enclosure.

With the following code :
```
<div wicket:enclosure="mylink">
   <a wicket:id="mylink"></a>
   <label wicket:id="mylabel"></label>
   <a wicket:id="myotherlink"></a>
</div>
```

When you click on mylink to refresh mylabel, wicket refreshes the enclosure tag, and call renderhead of behaviors of enclosure and mylink only, so myotherlink event is not bound

It can be reproduced in the quickstart.
I've also joined some pictures of the callstack to find easily where is the problem

I don't know if other versions are affected