TerminalInteractiveShell.editing_mode inconsitency

I'm just going to document this for the moment:

ipython 6.1.0
python:
- problem shows:
- 3.5.2
- 3.6.2b2 (and I think 3.6.1)
- 3.7.0dev [Python 3.7.0a0 (heads/master:a7874c7, Jun 26 2017, 21:58:56)]

O/S:
ubuntu 16.04
windows 10

`$HOME/.ipython/profile_default/ipython_config.py` settings:

c.TerminalInteractiveShell.editing_mode = 'vi'

Behavior:

with some history established:
- move up history w/ editor (e.g. `[ESC]k`)
- do some editing action on the line (no mods necessary - `i [ESC]` is sufficient)
- attempt to move to a different line in history (any line)
- e.g. attempt motion `k`
- also search `/foobar`: can select searched line, but no motion from result (except original line)
- expected:
- motion through history
- actual:
- stuck on current line