Inline comment glitch in parallel diff

When I try to add an inline comment in a parallel view, I get too narrow a comment box:

gitlab_diff_comment

Steps to reproduce:

  • Make sure you use "side-by-side" diffs by default
  • Go directly to any MR but without ?view=parallel or any other URL parameter)
  • Click on the "Changes" tab.
  • Try to add an inline comment