I’ve installed Sublime 3 (the dev build 3184) on a new Ubuntu 18.04 installation. I run xfce4 as my desktop environment, and have done so for years on an older laptop running 16.04.
Sublime works, but the main menu layout is clearly broken, due probably to some missing package or system-level configuration.
I’ve tried a fresh version of ~/.config/sublime-text-3 with no effect. No other applications that I’ve played with so far have the same problem.
edit — the editor looks fine when I run a Unity session instead of xfce4, so there’s something funny with some theme manager or something like that.