Left Click for Attack + Move

Hello,

So if I go to Settings>Hotkeys>Player Movement I cannot seem to change from MB2 to MB1 or from Right Click to Left Click. Is there an easy way to do this or is it even possible? I read something that there was a patch from 2 years ago that should have made this possible. I think it was Patch 7.15. Can anybody offer some guidance?

Thanks!