We have merged a couple changes so that jQuery UI is not loaded by code that doesn't need it. See https://bugzilla.wikimedia.org/show_bug.cgi?id=55550 for details. That means gadgets and user scripts that use jQuery UI should explicitly load the appropriate module. https://www.mediawiki.org/wiki/Extension:Gadgets has info on adding gadget dependencies. User scripts can use mw.loader.using (https://www.mediawiki.org/wiki/RL/DM#mw.loader.using). A list of jquery.ui modules is at https://www.mediawiki.org/wiki/RL/DM#jQuery_UI . There is one remaining issue that may affect a few wikis. If your wiki uses jquery.ui buttons in wikitext, the styles will not be loaded unless something explicitly loads or depends on jquery.ui. If you notice styles missing from your wiki, you can add: // Load jquery.ui.button so button styles work in wikitext mw.loader.using( 'jquery.ui.button' ); to the site Common.js Don't do this unless it's actually needed, since this does have a performance impact (although it is not loading all of jquery.ui). If you do add it, please include the comment so people know why it's being loaded. This will roll out to the test wikis, plus MW.org, 2013-10-31, the remaining non-Wikipedia wikis the 4th, and the Wikipedias, the 7th. Matt Flaschen