Yeah, it's in there. And as I stated in another thread, it's not obvious that you can do it. And apparently it has a bug where sometimes you get the red circle saying "no you can't do that" and sometimes you get the blue circle.
Hell, I see the red circle all the time when moving units around. The path finding algorithm seems to default to saying "no" and then takes a second or two before it says "oh, okay, yeah, you can do that". So go to move a unit to a tile, get the red circle. Wiggle the mouse and then it decides to change it to a blue circle.
So, if the UI sometimes lies to you, I'm not surprised that very few people have figured out that you can swap unit positions if they have enough movement points.