When not using clean_markup, widget results will be generated in ul > li lists, and the first result will look something like this:

<li class="lw_item_1 lw_has_image">...</li>

If you set use_category_classes=true for an event with these Event Types selected:

• Arts & Performances
• Lectures
• Student Events

Then the resulting wrapper will look like this, allowing you to theme special CSS styling for individual event types:

<li class="lw_item_1 lw_has_image lw_category_arts_performances lw_category_lectures lw_category_student_events">...</li>