it its set to no effect its not calculating something, kinda like deleting the history. It knows its there its just not useing it. you need to turn it back on before you can remove it or it will give you problems.

its kind of like futsing with IKs and moving the pivot point on the wrong anchor and having the chain freak out. you cant undo it because it didnt register the change in the history.

simplar principal but a diffrent problem.

i would also like to say that I have a VERY limited knowlege of how to use those values so if i'm blowing smoke its just because I have bad information ^^;