Screenshot

Steps to reproduce:

1.Open a page with VE which contains a image at the right

2.Select the image

3.Go to the Media Settings> Advanced Settings

4.Move the position of the image to center

5.Select some other element or just click outside the image anywhere on the page

Observed result:
Cannot select any other object in the page
An error appears in the console:
Uncaught Error: Offset could not be translated to a DOM element and offset: 227

See the screenshot attached.
Test Environment: http://en.wikipedia.beta.wmflabs.org/
Browser: Chrome Version 26.0.1410.65 & FF 25
Page:http://en.wikipedia.beta.wmflabs.org/wiki/Ehat?veaction=edit

Version: unspecified
Severity: normal

Attached: