The #intro item is common to all activity types. It is not a target of JavaScript and in addition is not really different from any generalbox element in most cases. It could very easily just be another notification box.

Currently:

<div id="intro" class="box generalbox"></div>

Recommended:

<div class="intro generalbox"></div>

Context: http://docs.moodle.org/dev/Standardize_classnames_and_layout_to_facilitate_theming#.23intro_ID_a_classname_instead