I gotta get this one I have seen it a bunch of different ways.

Sitch: Start of game, jump ball center circle.
A1 taps toward sideline A2 muffs and fumbles ball OOB
Ball awarded to B at spot ball went OOB.

Who gets possession arrow?

If A had possession before dropping the ball out of bounds or stepping out of bounds, then B gets the ball on the violation and gets the next AP as A had initial possession.

If no possession and A causes the ball to go OOB, B gets the ball on the violation and A gets the arrow as this would represent the initial possession.

A violated by knocking the ball out of bounds, but never controlled the ball. Therefore, the possession arrow is set to A when the ball is at the disposal of B for throw in.

Thanks guys, that's the way we did it last night but had a couple of people challenge it.