Fixes editing and page association. It works!

\o/ [#52818341] AnimationPanes can be created by authors (non-admins) and are automatically associated with their pages. (This turned out to be the same problem: failing to associate the pane with the page meant the authoring algorithm couldn't tell if the user had permission to edit it.) The UI for editing the pane is the same as for creation, and panes created by the authoring tool run in the runtime.

https://www.pivotaltracker.com/story/show/52818341