Place Reverse Curves

I am trying to use the place reverse curves tool in Geopak.  I want to set the delta of the first curve.  The tool appears to allow for that, however, each time I check the box and type in the delta, when I go to place the reverse curves, the box is automatically "unchecked" and therefore unconstrained.  It appears to only allow one to set the length, not the delta or direction.