[chimerax-users] Using name of selection with rmsd command

Hello! I've been trying to use "sel sel res t; ~sel H; ~sel @N,CA,C,O; name target sel; sel #2:23; ~sel H; ~sel @N,CA,C,O; name original sel; rmsd target to original" to find the RMSD of just the target's side chain to the original, but I keep getting a reported RMSD of 0.000. I click on an atom of the target residue, then use "sel sel res t" to select the whole residue, "~sel H" to deselect hydrogens, " and "~sel @N,CA,C,O" to deselect the backbone. I then name the left-over selections. I thought this series of commands would work but it's giving me an incorrect RMSD. Is there a different combination I should try? Thank you, Alex