Can anyone tell me what the new play plus sign button is at the top of the screen is for and how it works?
That is the same function as the >| button in prior versions. The button icon was changed to avoid confusion for people who thought it was play next button. What it actually does is allow you to play past the duration you configured until you manually fade it or it reaches the end. The theoretical use was for a batter coming to bat at the start of an inning when you might have more than the standard 11 seconds available before they were set at the plate.