When I try repr sphere :64 or repr stick :64 over the default presentation of my protein in ribbons [the heme group is in sticks, as are automatically selected residues in close proximity], as suggested in today's user mail, it doesn't work. It only seems to work if all atoms of the protein are displayed. I can only reset the display mode of the residues Chimera has chosen to show in addition to ribbons using these commands on the default mostly-ribbon display. How do I get the protein mostly in ribbons with a few residues in stick or ball & stick? While I haven't worked through the entire tutorials referenced in today's mail, the examples of repr shown early on do not do this; they start from a display of all the protein's atoms. Thanks! Irene Newhouse