Ever since installing WordPress 4.3 I had been noticing some weirdness with the admin sidebar getting mangled. Especially when on the WordPress dashboard. I initially thought some of my admin customizations were causing the problem, but I eventually found some forum links where folks were having the same issue.
I ended up finding some fixes and adapted them into this quick snippet which can be added to the functions file to fix the issue.
<%= gist “ryanburnette”, “ec78ae7872f906f012d9” %>