Hmmm had a look for the "fill all empty space with music" button and it looks like the latest version of iTunes might have deleted this as an option.

My joy remains unrestrained.

Main system; 861v8 ID41, DSP8000SEU fronts with DSP5500 centre and DSP7000 rears (all in lovely silver) 504, HD621
Second system 861v4 ID40 LPS, G98DH, 504, HD621, 2x DSP5200 with DSP5200 centre
MD600 tucked away in study. Lots of other Meridian!