AniMate 2 acting very strangely in DS 4.10

Ken OBanion

I've been tinkering with dForce a bit (finally got one of the Medieval Cloaks to simulate without exploding or falling apart -- God bless weight maps!), and while attempting to animate a walk with dynamic cloth, I've noticed some rather bizarre behavior in AniMate 2.  I add a start aniblock to the timeline, then a corner-left aniblock, followed by a walk-cycle aniblock.  If I select any aniblock and attempt to drag it along the timeline, the representation of the aniblock (the blue rectangle) will jump well to the left of the cursor, to a point that is even before the start of the timeline!  Attempting to drag it back to where it was supposed to be causes other aniblocks to "trade places".  I've had to delete everything and start over several times, and it's starting to honk me off!

This kind of behavior didn't happen with 4.9; what changed, and how do I fix it?