I'd like to move the MoverBase-based movers off of SingletonContainers :-). This would simplify their implementation, make running with them slightly more efficient, as well as simplifying their usage as. It would also harmonize the various movers a bit. And, of course, it would break various existing code. I could provide a backward compatibility functions, but I am reluctant to do that as providing the functions is a bit complicated and the semantics have changed (that is the particles are no longer shared) and, while I don't expect the changed semantics will make any difference to anyone, I would rather people inspect their code just to be sure.
So the new constructors for the BallMover and NormalMover would be
BallMover(ParticlesTemp particles, FloatKeys dofs, double radius).
or
BallMover(ParticlesTemp particles, double radius).
This will also remove some of the direct accesses to the contents of containers to move towards supporting filters on the all pairs containers and such things.