I installed your (great!) plugin on my Website and tried to HTML-validate the website with the online validation service http://validator.w3.org.
The validation fails because of the following link, put by the Shortcode ultimate plugin:
<link rel='stylesheet' id='su-box-shortcodes-css' href='http://www.paradiso-systems.com/wp-content/plugins/shortcodes-ultimate/assets/css/box-shortcodes.css?ver=4.2.0' type='text/css' media='all' />
This link has been added in the Body section.
According to this comment the link should be put in the HEAD section instead, in order for the validation to succeed.
Do you have any suggestion on how this could be solved?
BTW, great plugin!