All of a sudden, when in PRV I can't click in the time line to change the Now time, though dragging up and down to zoom in and out works fine. At the same time, the snap settings are no longer working. No matter what I select in the Snap settings, it wants to snap new notes to 1/4. If I change the Grid resolution to a specific value that works, but follow Snap Settings does not. And the tick marks don't change if I say follow Snap Settings. This is true in multiple tracks. I have closed and re-opened PRV, closed and re-opened SONAR entirely , to no avail. Never seen this problem before. Seems to be project-related, because everything seems fine in another project. Help!

You are aware that the PRV also has a snap grid all of it's own? Look on the right hand side.
When it is enabled, it overrides what is set in the main snap grid.

OH!! No, I never noticed that! OK, that was the problem. THANK YOU!!
 
...just read through the online help on the PRV snap settings....
 
WOW WOW WOW!! I am going to make so much use of this. Now I'm so glad I accidentally enabled the PRV snap, otherwise I would have never learned about it. This is a good day. Thank you again!

Yup...    Independent PRV snap rocks.    Just sayin'.