Horizon Walker Question

[Enzario]

Lately, I've been seeing a lot of people on the boards including a dip into Horizon Walker for the Shifting Planar Mastery ability, allowing you to use a spell-like ability to Dimension Door every 1d4 rounds. However, the wording seems to contradict what most people think:

Shifting (Planar): You have the supernatural ability to use the ever-shifting nature of planes such as Limbo and the Plane of Shadow to travel faster. You instinctively anticipate shifts in the reality of the plane that bring you closer to your destination, giving you the spell-like ability to use dimension door (as the spell cast at your character level) once every 1d4 rounds. You gain a +1 insight bonus on attack and damage rolls against outsiders and elementals native to a shifting plane, such as slaad and shadow mastiffs.

Now, to me, this seems to say that you can use this ability only while on one of these planes, however, many people seem to take this to say that you can use the ability wherever and whenever you want. Opinions? Which is it?

[NEO|Phyte]

Horizon walkers take their terrain mastery with them wherever they go.

You get the ability everywhere.

[Enzario]

Wow. Okay then, thanks. That clears up several issues I've had with builds that people post.

[Mr the Geoff]

It says elsewhere in the class description that you take your mastery wherever you go, so in the same way you would get to keep your fire resistance from the fire planar mastery on the material plane, the same is true for the dimension door ability.

[ShneekeyTheLost]

However, you need more than a dip to get it. You don't start getting the planar masteries until 6th level of the PrC, which needs about five or so levels of Ranger itself.