I discovered that I accidently created an empty submenu in my Actions list so I realized it was possible
I could not find it in the documentation, but Googling I found:
While I personally find the technique a little counter intuitive, it works well using the actions dropdown
Suggestion - if it's not in the documentation, it should be added since it's very useful
Suggestion - if it IS in the documentation, it should be made a little more prominent
Suggestion - what would be much easier to setup would be a real multi-level menu where you can insert a new sub-menu and drag actions into it
Did you know that if you add an & in front of any letter in the name of the action then the letter becomes a hotkey that can be addressed in a combination with Alt+Menu hotkey+user-defined action hotkey?
Yes, but what I did not know was that MP3TAG uses # to create a submenu entry, even without the &
Silly example: If I have 3 actions:
Change &Title#From Artist
Change &Title#From Album
Change &Title#From Filename
The actions dropdown will show
This submenu capability is a pretty handy feature that I had been looking for and couldn't find in the documentation
See also ...
Hidden Feature inside MENU Tag Sources
I do not remember from where I have got it before.