Fixes the menu bug introduced by giving separators a role.
Fixes the menu bug introduced by giving separators a role.

wikimedia/MathJax,GerHobbelt/MathJax,jinntrance/mathjax,thomasjm/MathJax,dpvc/MathJax,thomasjm/MathJax,jinntrance/mathjax,GerHobbelt/MathJax,thomasjm/MathJax,thomasjm/MathJax,thomasjm/MathJax