To help keep my character's feet on the ground when I use a number of animations from the preset library, I often use align clip (usually align left foot etc). But for some strange reason in CTA3 the align clip options are sometimes greyed out and I cannot work out why sometimes it is available and sometimes it is not?  I am using 3d motions from the library, and sometimes I may modify the preset animations slightly. I have tried flattening clip, but that has made no difference.
This is driving me nuts and wasting a lot of time... any ideas of what I'm doing wrong and how to get Align Clip working again?