Clicked on the entities window and now my editor is frozen:
I’ve only got a plane and sphere in a subscene and a couple scripts.
I have this too! please help
force quit unity from the task manager
Raised this internally, @spinaljack – can I get a few more details from you?
Which version of Unity are you using?
Which version of the Entities package?
In the scene/subscene: is the subscene containing the objects nested under another gameobject, is the subscene nested under another subscene?
If you can file a bug report, that would be awesome, so we can get a repro project. Thanks! 
I’ve not had the same issue again but it was unity b13 with the latest version of entities back then, probably exp.12
The objects weren’t nested. The subscenes weren’t nested.