Head Height

[Plymouth]

Does Vizard have a default setting that constrains changes to the height of the viewpoint?

I'm tracking movement with PPT. Whenever I try to raise my head's elevation (jump) there's no response and when I try to lower it (crouch) it suddenly moves my headheight to the ceiling and then lowers it from there. I'd like to be able to move my head around in three dimensions without getting strange effects.