AFAIU, Instances of Atom, Bond, Fragment, Residue, etc. are not supposed to
be used without parent Molecule - they lose functionality and may crash in some
cases (patches submitted to gerrit)
However, constructors of these classes are defined like
so it’s very easy to write e.g.
Atom *a = new Atom;
and get zero parent. Also, nothing prevents from using e.g. some QWidget * as
parent of object.
Why constructors like Atom(Molecule *parent) were not used instead?