271550778f
Explanation: there's a CSS technique for making images responsive by applying max-width: 100%; and height: auto; to them. This messes with the bundled Xinha WYSIWYG editor. The buttons in Xinha's toobars can't have max-width: auto;, it makes them disappear. So far, I haven't found a way to overwrite this for the toolbar images only due to selector specifity. Either need to find a way or find a way to make other images (media, actually) in the backend have a class which assigns the responsive media CSS to them. (Or drop Xinha for good, but that doesn't seem to be an option.)