MooTools 1.2 AJAX problem

I have a problem with the use of AJAX in MooTools 1.2. The thing is that when I load a page using AJAX the onclick events in IE are not parsed in the response. This did work in MooTools 1.1.
When I load a piece of XHTML through the Request.HTML which contains the following the onclick doesn't work:
<button onclick="alert('Show something');">Click me<button>

You can test it using the following buttons:

Load content
Content will be displayed here...




View the javascript source.