>> in case you run into this issue when adjusting your setup, the Ctrl +/- thing is meant for use with the "keypad" + and -. The + and - on the QWERTY part won't do it.
Ah ha ! Excellent tip ! Thanks ! That's why the darn thing never worked for me over many years on my Linux setups as I only ever have latops
Looks like it's Ctrl , Alt, Fn +/- for us laptop users !