The dropdown for some issues fails to expand

[eduardoboucas]

Steps to reproduce

1. Inspect https://developer.mozilla.org/en-US/
2. Open the Compatibility tab
3. Open the compatibility details for IE 5
4. Find a style sheet with a @font-face issue (at the time of writing, it's the second one on the list)
5. Expand the dropdown next to @font-face

Expected behaviour

The dropdown expands.

Current behaviour

The dropdown fails to expand.

[lefta]

I did just try it in case one of my PRs would have fixed it, and the dropdown expands correctly. So, I tried with your master branch just to be sure and... I was not able to reproduce it.

However, it reports 9 problems, but there are only 3 @font-face in the stylesheet.