hi, we are using secondary structure restraints to enforce RNA base pairing. it seems if we use insertion codes , it causes a crash with this error: /usr/local/phenix-1.8.1-1168/cctbx_project/mmtbx/secondary_structure/bas e_pairing.py", line 508, in identify_base_pairs basecode_1 = atoms[base_1[0]].fetch_labels().resname.strip()[0] IndexError: Index out of range we are using syntax like this: refinement.secondary_structure.nucleic_acids { base_pair { base1 = segid "WTF" and resseq 78 base2 = segid "WTF" and resseq 98 } base_pair { base1 = segid "WTF" and resseq 79 base2 = segid "WTF" and resseq 97 } base_pair { base1 = segid "WTF" and resseq 80A base2 = segid "WTF" and resseq 96 } } we also tried putting it in quotes with no luck it works if we use resseq 80 this is with version Version: 1.8.1 Release tag: 1168 thanks jpd