Auto scoll in the key editor has a frustrating standard behavior. Consider this situation for purposes of illustration:
Imaging that you have six measures displayed, measures 10 thru 15. The cursor is right in the middle at the start of measure 13. Hit the space bar to play (with autoscroll enabled) and let it play long enough to scroll. Hit the space bar again, and what do you see?
The cursor is back at measure 13, but the measures displayed are 8 thru 13. It seems to me that if Cubase is going to make a judgement and not simply return to the original state (measures 10 thru 15), it should assume we are interested in editing MIDI after the cursor position, not before it. So, it would be OK to guess that we wanted to see the cursor at measure 13 and have the display range be measures 12 thru 16. It would also be OK to just go back to the original range. It’s not OK to hide the measures likely to be of most interest which is how it works now.
The way things currently work, an additional scrolling operation is nearly always needed, which is beyond annoying.