For Control modifier I set "Shift+L" for testing purposes and previously default was moved to the right. Problem is I can not delete "Shift+L" and keep only the default "Left Control". The given instructions do not work, "Shift+L" remains as primary. I have changed other keys and I do not want to lose them by using "reset to default" again. Also "Control" does not work any more, even if it is designated as secondary.