@alexivanov @moshpirit Expanding the Editor area down from an Action bar? Why this idea didn't come to me? :-) ...
Anyway, current problem is not caused by direction of the Editor growth. It is caused by too large maximum height of this growth.
I will try to do this:
1. Return Action Bar to the same place it was before (i.e. not covered by Editor)
2. Allow to switch to a full screen mode with action bar hidden , and return back - by tapping read-only area of the Editor.
?!