Does "Property Law" include "Intellectual Property Law" or are the two areas separate?

Protecting Intellectual Property Rights

Intellectual property is a significantly different form of law drawing on other areas (notably unfair competition law, especially for trademarks; law of agency; business law; etc.) but is fundamentally its own "thing."

A notable example of the difference is the phrase "Possession is 9/10ths of the law." This may be true in property law, where a possessor has superior rights to most everybody but the true owner. However, it would fall flat in IP, where your status as the legal rightsholder is the most important question.