R.K.
It sounds like normal 2 yr old behavior to me. At 2 kids realize that they have the ability to make decisions and they want to make all of them all the time. They just don't have the experience to make good decisions. Instead of taking him out of the situation just say "no" very firmly. Tell him that not everything is "mine" and that the toys and chairs at the library are not his but there for all the children to play with. You have to have this talk often because his memory is not that great yet either. He will outgrow this behavior, it is just a phase.