A number of games, Emacs, and the terminal make extensive use of the Alt key. Can Unity be configured to respect this key, rather than launching the HUD with it?
Open the System Settings application either by going to Session Indicator in Unity panel, or by searching for System Settings using the HUD.
Then go to Keyboard > Shortcuts > Launchers. You can redefine the HUD key with the Key to show the HUD option. Pressing Backspace will disable the HUD shortcut altogether.
If you set it to Alt manually, the setting distinguishes between the left and right Alt key. So if you want to maintain general behaviour and still use Alt combinations, this may be an alternate solution for you.
