Extended/limited range button missing

With the recent update (5.5, and 5.5.1), I've noticed the plus/minus button in the bottom left corner that extended or limited the range of certain instruments went missing. Is this a bug or intended? Or was it moved and I can't seem to find it?

Edit:

Strange, I opened Pianoteq 5.5.1 on another machine with the same result. Then I restarted the program and the plus/minus button reappeared. Opened it on my Surface 3 again and also reappeared. I know it doesn't show for certain instruments, but I recall not seeing it for any instrument. Weird!