I'm late to this party, but me too! I've been trying to power user harder lately and learn every hotkey I can. Presonus Studio One isn't the only software with this problem. It's all of them on Windows. Windows seems to guard the alt key very jealously for some reason. This is a feature, not a bug, of Wangblows— I mean Windows. Thanks, Microshaft— I mean Microsoft! I've just spent hours looking for a solution. There seems to be a third-party software that some people say MIGHT work. I haven't tried it yet because I'm just so offended that this is an issue, as if OS makers haven't heard of software with hotkeys!