Disable Movement when jumping

So after a bunch of searching and tweaking I've finally gotten my actor jumping the way I want it to. However, once it's in the air I don't want the player to be able to move it left and right. I've searched the forums, and the cookbook, but haven't found a suitable answer. After messing around with different rules and attributes I can't seem to find any that actually work.
Does anyone have any suggestions?
Does anyone have any suggestions?
Comments
Constrain Attribute self.position.X to self.position.X
Try that.
Cheers
@JohnPapiomitis: Ack! I knew it was going to be something simple. Thanks John that worked perfectly!