Optional GM Rule - Ignore Trait Restrictions not selectable

When trying to select the optional rule "Rule - Bypass the trait restrictions", PCGen gives me an error message stating "You cannot select any more abilities."

I tried selecting this rule at various points in the character creation process - Right off the bat, after having picked 2 traits already, and after I had finished creating a level 1 character. In all cases it gives the same error message.

Note: It does let me add the Hero Points optional rule, as the Advanced Race Design, and Anti-Hero options, so that part works fine.