In the template code you were observing an event 'node' on which you *directly* did a postback with a certain action to do the animations. That felt unnecessary: the "take_down" and "bring_up" actions are not really needed unless you want to do animation. To simplify, I just refreshed the _left and _right templates from the page callback and that's it. I renamed the emitted event to 'node_status_changed'. However, your approach is correct if you want to be able to do these types of animation.
That also takes care of flushing Zotonic's cache. Now you're flushing everything all the time, which leads to a lot of unnecessary computing.
I added a category "node" to the datamodel, since your application depends on it. Nice for new installs.