Hi in another thread i reported that i was having trouble with Renoise 3.0.0 b3 and in particular with going fullscreen as it was causing problems with minimizing.
I have found that by dragging the Renoise window decoration i.e the top of the window that the desktop provides, right up until you are hovering over the top bar of the actual desktop it will then go fullscreen. This has lead me to find that there was a section of Renoise at the bottom that was not visible, which now exposes the button to switch views between dsp pane and automation pane. I must put this into a bug report or at least link to this thread, well i hope this can be of some help to you ubuntu users 
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I have just realised that im actually just maximizing Renoise with the above method , its early here and i havnt slept all night uk time lol