User-defined adduct definition does not include some elements

[robertsamples]

I would like to include [M-2H+Ce]+ (mass 137.889792) as a user defined adduct however this does not appear to be possible. The corresponding lanthanum adduct is determined correctly:

however this is not the case with Cerium

It would preferable from the user's perspective to have a flexible adduct definition where an arbitrary name and mass delta could be specified, or for all elements to be available.

[Bujee415]

Hello!
Sorry for the late notice!
We added cerium to the list, so you can use it with our newest release.
Thank you,
Bujee