Out of Bounds - Eligible player?

[baref2008]

I have been a ref for about 10 years, but have been away for the last couple and am finding that the layoff has made me second guess some of the more rare plays that happen. One that has happen recently is the following. A1 is attempting a throw in on the baseline and passes to A2 in the corner. A1 then re-enters the court and recieves a pass from A2...A1 scores a layup. On two occasions I've had the opposing bench screaming that he was "out of bounds" and isnt eligible to score. It's my understanding that although he was out of bounds for the throw in, as long as he has reestablished himself on the court by having both feet in bounds than he is eligible. Who's right?