This is probably beyond the scope of what we can reasonably help with on the forums. By Unix systems, I'm guessing you mean some distribution of Linux. If that's the case, the Alt key is really being eaten by your Window Manager. Assuming you're using latest Ubuntu, that Window Manager is Gnome. Annoyingly, there is no way to configure a different modifier for the Window Manager (Here's some details: <a href="https://askubuntu.com/a/263863" rel="nofollow">https://askubuntu.com/a/263863</a> ). One option might be to switch to a different Window Manager that doesn't depend on the Alt key. There may be hope in the future. Chromebooks in particular are incapable of sending Alt to the browser, likely for similar reasons. There has been much discussion in the bugs forum about that recently and there is some indication an alternative (such as a menu option to choose circles) may appear in the future.