I was pretty frustrated last November when I bought a new Macbook Air and experienced weird behavior in Photoshop CS5. Brushes would stop working. Tool icons would freak out. This was discussed at length on the boards, and Chris from Adobe said everyone at Adobe and Apple were aware of the issue due to video card incompatibilities (?) and Lion.
Happy to report that all that behavior has dissapeared with Photoshop CS5 running on Mountain Lion (beta v1). It works as it was meant to. Yeah!
Thought I would report back as all those threads have been locked for awhile.