say you have a ball with 2 legs, as such:
now when you first draw the two legs the nulls will be childs of the the bottom leg bones (bone 6 and bone 7), which would, as i understand it, cause the whole skeleton to move if i moved the body bone (root/bone4).
now if i kept it like that i wouldnt be able to move the body while keeping the legs in place, and so i unparented the null for each leg.
from what i understand, that should cause the nulls to not be affected by moving any of the other bones, and if i moved the body, which would again move the feet bones, they would simply always be pointed towards the location of their nulls, and fall in place if they came close enough.
Though, it seems that the nulls are still affected by their feet.
well, if you understood that, maybe you can point me in the right direction ^^