My toolbar in Simulink keeps disappearing and reappearing

I'm running a student version of Matlab 2016 with the Simscape Power Electronics library. I have Windows 10.

I have attached a screenshot of what my problem looks like. My problem disappeared for a while after it first occurred and I was able to work normally for a while, however it has returned.

So basically, when I open a simulation model (blank or pre-existing) the toolbar is missing with all of the shortcuts. I've looked here:

http://uk.mathworks.com/help/simulink/ug/summary-of-mouse-and-keyboard-actions.html

and found that only some of these keyboard shortcuts work. Unfortunately opening the library and running the simulation are not among the working ones. Essentially, I can open Simulink, but not much else. I've checked my preferences and could not find anything relevant.

Can anyone help?

I'm hoping I did something silly like hitting one of the function buttons (f1, f2, f3...) by mistake and that this is easily fixable, but I don't know what to try next. Any and all advice is welcome. If more information is needed please reply and I will supply it.