Using Alt as the default hotkey for opening the HUD is not optimal
Ctrl, Alt, and Shift have historically been used as modifier keys and I believe that by themselves, should not be bound to any specific action (currently opening the HUD) by default as this interferes with too many existing functions.
=====A USER STORY=====
It's mostly an issue when I'm in the process of hitting Alt+Tab or Alt+` and then decide that I've changed my mind and I let go of Alt. Instead of nothing happening, the HUD appears which is not what I would expect.
|Changed in unity (Ubuntu):|
|status:||New → Incomplete|