Issue
Semantics - The expand/collapse buttons, icons and folders should be coded using a <button> element and not a <a> element, as activating them is not leading the user anywhere (as would a link).

Standard Level
WCAG 2 A 1.3.1 http://www.w3.org/TR/WCAG20/#content-structure-separation-programmatic

Impact

Example Link
http://demo.moodle.net/course/view.php?id=625
Group links like course in the settings block show as links and should be buttons due to their purpose to only expand a list of links and not navigate the user to a new page.