[chimerax-users] No chains in AtomicStructure

Hi, I have created a python plugin that uses AtomicStructure() class to create a model based on the pdb file and custom trajectory file. The problem is that after creating the structure (adding residues and atoms) it has no chains. Due to this issue, I cannot use some of the ChimeraX features (e.g. rainbow coloring) - at least I think this is the reason. While adding new residues one has to specify the chain_id, but even if I do it those chains are not created automatically. Do I have to create chains separately or there is something that I am missing here. Would be grateful for your help. Best, Dominik