plone/plone.app.theming — pull request #33 by datakurre (2014-11-27 15:33:56+00:00)
Title: Fix issue where skinsSettings does not have use_popups attribute on Plone 5

I'm not sure about all things going on for Plone 5, but this was required for me to get theming control panel open on Plone 5 (master).