Switch templates unresponsive

While this used to work fine, today, using switch templates is pretty much unresponsive: When I select a different template, it is not rendered immediately, and neither upon save or close of the component parameters dialog. I only get to see the new template when I publish my CM changes.

To reproduce this, I'm installing some Essentials features which have extra templates, such as news, events, FAQ, blog, simple content. Rebuild and then try to use switch templates in the CM.

I'm using Chrome on OSX.