macOS Sierra - why did my Calendar stop free-scrolling? I was able to freely scroll forward and backward in time. I can only go forward via the arrow keys one page at a time now. No idea why this is happening. 

I tried a workaround at one point by clearing my calendar (methodical removal of plists, etc...) then restoring it from iCloud. After that restoration it didn't work. Next day scrolling worked. Day or two later, scrolling calendar stopped working and still doesn't.
Put two fingers on the page and move it to the left or the right, stop when you want. It is still there.
The arrows move a page completely, set to day, week or month when you want to use the arrows.