When I want to autocomplete a function I can't use Tab key to expand what I typed in. If I press Tab, it escapes the popup suggestion menu. Autocomplete only works if I press Enter. Furthermore, once the function has been expanded with Enter, I can't use Tab to switch over the arguments of the function. Pressing it does nothing.
How can I find if it is a problem related to my own installation of Mathematica or maybe a key conflict?
I'm using Mathematica 10.3.0.0 with a Student Edition license and running Elementary OS 0.3.1 built on Ubuntu 14.04.