In an older mouse, I could "click" the scroll wheel to the left as an additional, programmable function button. I just purchased a MORE expensive and advanced MX Master 3 mouse. The scroll wheel obviously has the same feel of a left-side click, but there is no way to program the button. Also, the thumb-rest button cannot be programmed easily (to open the Calculator). It requires a "double-click" instead, which then opens the task view prior to opening the calculator. I LOVE the feel and accuracy of the more advanced mouse, but I'm surprised at the awkwardness of the button programming. I've downloaded the BETA version of the software, but the options remain the same. Please let me know if you have any questions or solutions for me. Thank you! Henry Oliver