I'll attempt to confirm or deny this at home on my PC tonight, but here at work when I create a new layer the first click off it in the layers palette, AR3 drops me back to the base layer. After that, I can no longer select the higher layer. I can re-organize them, bringing that layer to the bottom, but I can't paint on anything but the base layer after that first click.
Steps to reproduce:
1. Create a new document.
2. Open the Layers Pod.
3. Create a new layer.
4. Click back to the base layer.
5. Try to click back to your new layer.
I've placed the platform and specs in the title header but for the sake of being thorough, I've attached a PDF of the system information profiler's dump (minus the applications stuff, just too much of that.)