I believe the code in MediaWiki:Gadget-Edittools.js is broken after phab:T30856. Clicking on buttons prints the following error into browsers console:
TypeError: mw.toolbar is undefined; can't access its "insertTags" property
Topic on Extension talk:CharInsert
We fixed on fawiki with the following change: https://fa.wikipedia.org/w/index.php?title=%D9%85%D8%AF%DB%8C%D8%A7%D9%88%DB%8C%DA%A9%DB%8C%3AGadget-Edittools.js&type=revision&diff=24787771&oldid=24786882 .