Re: Disable zoom slider on MX 3200 keyboard - Logitech Forums: "1. You can disable the dynamic slider and the 100% hot key by pressing FN Close. You can enable them by pressing FN Doc Flip.
2. You can enable or disable the beep sound of the dynamic slider by pressing FN Search Pics.
*Note that the FN key is located beside the right Alt key"
Alternative: Install uberOptions ( http://uberoptions.net/ )