Spline Ik and Rigify

I added some bone chains to my metarig and generated a rig. Now I am trying to add some controls to those bones. Specifically, I am trying to add a splineIK to the bone chains. When I select a chain and try to add SplineIK from Constraints menu, I get an error message saying I have to choose bones. I have bones selected. Why am I getting this message? Thanks.

Neilford

Figured it out. Thanks.

Neilford