Hello Rene,
The plugin "System - jQuery Easy" is messing up with EasyBlog's jQuery. As soon as I turn the plugin off, it seems to be working fine. The only way for this plugin to co-exist with the composer is to add the following in the exclusion,
http://take.ms/mcKeG
Ideally, plugins / extensions should respect tmpl=component as this is an API that Joomla provides to allow extension developers like us to render a full page on our own without any interference.