User blog comment:Kirkburn/Technical Update: March 3, 2015/@comment-452-20150303185952/@comment-452-20150304013943

"...remember to collapse the right rail and update their CSS accordingly after this update."

Speaking of which: someone didn't test section editing with the right rail collapsed. I've been experimenting, but can't find a good place to put the section comment.
 * Although an edge case, this can happen: http://preview.community.wikia.com/wiki/Community_Central:Sandbox?oldid=1445180&action=edit&section=5

Since it's uneditable anyway, it would probably be best to just hide it completely - it shouldn't be a surprise to anyone to find that the name of the section they were editing is displayed in the edit summary. However, I notice that the maximum number of characters in the edit summary is not reduced due to the number of characters in the section heading, which might cause summaries to be truncated. (I personally hit the limit at least once per week.)
 * That last paragraph may be irrelevant - currently the section comment isn't added to the saved summary - I'll test it again once the update occurs.
 * Yep - the the update is now live, and NO automatic comments are added to the summary, including the standard "Undo revision 1445328 by [[Special:Contributions/452|452] (wall)"]

Additionally, there is a typo in MediaWiki:Wikia-editor-preview-type-tooltip.