[IMP-dev] bug in core::Centroid class derivative propagation to fine particles?

I was wondering whether there is a bug in derivative propagation in the core::Centroid class - is anybody else using it?

As it is now, the derivatives of the centroid are copied to the finer particles as is, using the DerivativesToRefinedas class. Shouldn't the derivatives be rescaled first according to the mass contribution of each fine particle to the centroid?

For instance, let p1 and p2 be particles of masses 10 and 20 respectively. Then if a derivative of 3 units is accumulated in C, then right now, a derivative of 3 units is also copied to p1 and p2 each. Shouldn't this be reweighted such that p1 get 1 derivative units and p2 gets 2 derivative units?