My Alt key started opening the HUD - how can I change it back? [duplicate]

I am not sure how it happened, but my Alt key started opening the HUD. (I.e. like the Super key), losing focus out of the running app.

How can I disassociate it from openning the unity menu?

EDIT (OP here): I found an answer in How do I modify or disable the HUD's use of the Alt key?

You can try to install the 'tweaks' app using the following code is bash (or other shell you might use):

sudo add-apt-repository universe
sudo apt install gnome-tweak-tool

Then you can start it with:

gnome-tweaks

After that, go to "Keyboard & Mouse" in the left menu. Then choose "Additional Layout Options" and go to "Alt/Win key behavior" and set it to "Disabled".

If that doesn't work, try setting the same field to "Alt is swapped with Win" and then back to "Disabled". (This shouldn't require a reboot, you can just change it to first and instantly to second).