accessibility issue

[earleyj1]

There is an accessibility issue in that the chevron icon is NOT accessible. To make it accessible, the span with the icon should have
<span aria-hidden="true" class="glyphicon glyphicon-chevron-down">&nbsp;</span><span class="sr-only">Expand/Collapse</span>

However, it seems that the "sr-only" class is being stripped out, and I'm not sure why. CKEditor itself allows it, so I'm thinking its the plugin.

I tried modifying
allowedContent: 'div(!collapsible-item*,panel*,collapse)[*];h4(!collapsible-item*,panel*)[*];a(!collapsible-item*,collapsed,panel*)[*];span(!glyphicon*)[*];',
by adding the class here, but it had no effect.