This is a little subtle, so it probably deserves a more detailed comment. There is only one Backbone view created on the container page, which is for the container xblock itself. Any child xblocks rendered inside the container do not get a Backbone view. To refresh a child xblock I need to make a Backbone view for just that element, so that it can fetch the updated xblock rendering. 

There are two alternatives I can think of:
1. Make all the child xblock views upfront so that they are available if needed by editing. This seems unnecessarily expensive to me.
2. Update the xblock without making a view. I could try to refactor the base xblock class so that it can render other xblocks than itself. That seems like it might be confusing.

Is a better comment enough, or would you rather I use a different approach?