Hi,
The Sum Formula node is really useful for working out some structures from LCMS ions.
Is it possible to refine the node a little. The user may know what atom types are present in the molecule (i.e. Br, Cl, etc), so it possible to have a box to type in known atom types to be present, and therefore any proposed molecular formulas which do not contain all these atom types are filtered out when the "exclude filtered" is selected.
Simon.