Setext Headings

[dylan-k]

Prerequisites

• Put an X between the brackets on this line if you have done all of the following:
  • Reproduced the problem in Safe Mode: http://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
  • Followed all applicable steps in the debugging guide: http://flight-manual.atom.io/hacking-atom/sections/debugging/
  • Checked the FAQs on the message board for common solutions: https://discuss.atom.io/c/faq
  • Checked that your issue isn't already filed: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aatom
  • Checked that there is not already an Atom package that provides the described functionality: https://atom.io/packages

Description

Level-one Setext headings do not get highlighted, although the level-two headings do.

Steps to Reproduce

1. Add two headings to your gfm file, like so...

Heading One
=========

foo

Heading Two
-------------

Expected behavior:

Both headings should have their underlines highlighted.

Actual behavior: [What actually happens]

However, only the level two headings are highlighted.

Reproduces how often: [What percentage of the time does it reproduce?]

This seems to happen every time. I have tried many different atom syntax themes with similar results.

Versions

Atom : 1.17.2
apm 1.17.0
I've seen this on Mac and PC and Linux