How can I rearrange exploding steps in an assembly in SW 2015?

Drag and drop doesn't seem to be working. I click and drag, but it's grayed out and never takes. I am using SW 2015 and I want to put a step I forgot further up in an explosion.

Yes, I tried to D&D both when not editing Explode Steps, and when editing them.

I am  using this for the animation of an exploding assembly, so order of steps is important.

SolidworksAssemblies