[rayiner]

Prior art continues to be a basis for invalidating a patent: the prior disclosure of an invention to the public invalidates a later patent. All first to file does is change the rule for deciding who gets priority in the unusual case where there are simultaneous patent applications before the PTO. Before, there was an inquiry into who was the first to reduce the invention to practice. Now, priority goes to the first to file. But a patent still cannot be issued if the invention was previously disclosed to the public either by the inventor (outside the one-year grace period), or by someone else.

[infogulch]

Thank you for clarifying that, I have had a wrong interpretation of it for some time.