[Chimera-users] About selection of atom

Hi, I cannot select atoms by using Ctrl+left button/double click left button by using my home PC, but I can do so by using my notebook. I guess the difference between my two computers is the input device. My home PC is using mouse while my notebook is using touch pad. I would like to know if there is any setting I can change, so that I can use the mouse to select atoms. Thanks. Best wishes, Frankie