Comment # 4 on bug 973599 from Dr. Werner Fink

(In reply to jaakov jaakov from comment #2)

> The bug looks somewhat similar to
> http://unix.stackexchange.com/questions/271886/emacs-got-blue-background-after-upgrading-to-3-20
> http://i.stack.imgur.com/vxre2.png
> though the distribution is different and the menu there is not shown.

If these is any more info I could provide, please report here.
This does look like a problem of latest gtk and special configuration.

I've just updated gtk3-metatheme-adwaita but do not cover the same problem.
Maybe gtk3-metatheme-breeze is the culprit