Atom highlight on atoms that do not show any precursors
The oxygen atom has a light green circle around it but no precursors are shown.
Target atom: CC(C)(C)OC(=O)N1CCC(c2ccc(OCCCOc3ccc4c(c3)OCO4)cc2)C(O)C1
Setting: default setting + IPP clustering on with rxn_class, group cluster turned off