Is anyone having issues with primatte keyer not being able to select BG/Foreground with AE CC 2015? I am not upgraded to .3 in AE, but I'm working in a shop so it's not up to me. I tried all of the trouble shooting tips from Red Giant's site.
Sorry I don't have any solution but you aren't the only one experiencing this. Someone I know has the same issue with AE CC 2015. I tried it and like you say it doesn't do any selecting, the colour picker worked but then you can't continue selecting to make the alpha stronger. I'm gonna need to buy version 3 soon.