Bug: Horizontal bar of square root symbol changes width part way through

Created by: OisinMoran

Issue Summary

While the horizontal bar works perfectly for the innermost case shown here there is quite an evident change in width on the outer ones. It seems this could be solved by extending the thicker regions to always meet the corner but I am aware that the square root signs are difficult from reading about other similar issues.

Steps to Reproduce

1. Go to jsbin http://jsbin.com/sofusojadi/edit?html,output
2. Zoom in more if you need to

Technical details

• MathJax Version: 2.7
• Client OS: Windows 7
• Browser: Chrome Version 60.0.3112.113 (Official Build) (64-bit)