This was added as the "center" mouse mode. Ticket #9183
I added a new mouse mode called "center" that centers what is shown in the
view (by moving the camera) and sets the center of rotation to the clicked
atom, residue, bond, pseudobond, surface point, volume surface. The
camera motion is animated over 10 frames. You can assign the mode to the
right mouse button using command
mouse right center
You can put that command using the ChimeraX, Settings / Startup / Execute
these commands at startup if you want this to be the default.
Note that ctrl-right click is not usable on the Mac in ChimeraX because of
a limitation of the Qt window toolkit. Qt always reports ctrl-left click
as ctrl-right click. So ChimeraX has no way to know when it gets a ctrl-
right click whether it is really a ctrl-left click or a ctrl-right click.
Since ctrl-left click is used for selection in ChimeraX, it always
interprets ctrl-right as ctrl-left click.
The new "center" mode like the existing "pivot" mode which sets the center
of rotation but does not center the view.