[chimerax-users] swapna command extremely slow for large structures

Dear ChimeraX team, I have noticed that on some structure I am working with, the swapna command is extremely slow, making it almost unusable for structure manipulation. For a single nucleotide substitution, ChimeraX froze for >5 minutes before finishing the operation (that particular structure had ~300 000 atoms). When I however first delete all proteins from the structure, the operation is very fast. What is the rate limiting step in the swapna command? Does it invoke renumbering of all atoms in the PDB file? Without having quantified it, I experienced similar behavior for the build replace command. Would be fantastic if there would be a way to speed this up to increase its usability! Many thanks in advance, Matthias