WTF? Separated object somehow linked to original mesh's translation

Blend Here:
http://www.pasteall.org/blend/12877

Hi,
Something is weird here. Not sure if it’s me, or something in the build I’m using.
This is Blender 2.62 Trunk for mac
6515_blender_trunk_45012
trying to model with BMESH.
(I think the model is currently Ngon free though, it opens in vanilla 2.62)

I made the crappy box modeled mouse mesh with the dark material.
I started the better mousehead object inside the first one in Edit mode, then used P to Separate by Selection.
Then I had two mesh objects. They don’t seem to be linked or constrained or parented to each other in any way I can tell, but when I translate either object, they both move?

WTF did I do wrong? I’ve never ran into this when Separating a part of a mesh into a new object.

You have Proportional Editing enabled in Object Mode, with a very high effect radius. Set it to None and the objects can be moved separately.

Hotkey for Proportional Editing is O-KEY (it’s a toggle, btw), so it’s fairly easy to accidentally enable it.

oh jeez

officially hanging my head in shame.

Thanks Chipmasque.