Board Thread:Support Requests - Getting Technical/@comment-27335883-20151203025608/@comment-1757994-20151203043722

It can be done using a custom button, but it's actually a glitch in the way mw-collapsible works.

You can define custom buttons with  that affect custom content with , where   is some keyword you choose, but can otherwise be anything. In the example below, I've chosen.



The reason this is a glitch is because it's a violation of HTML standards to define more than one element with any specific ID. ID should always be unique. Therefore it can't be guaranteed to work in every browser or even to continue to work at all in any browser.