Undo add-layer impairs animator window

Repro:
1. In the animator window, add some states to the animator
2. Create a new layer and undo by Ctrl+Z
3. The View is stuck on the new layer that's just been undone, it's impossible to switch to the base layer - the console spits out a message
4. Try adding something - it's possible to ad states (but what are you adding them to?) the newly added states cannot be moved around
5. Close and reopen the Animator window - the view is ok now.

Expected: select the base layer or the next layer on the list when an undo operation on added layer is performed