IMHO I think that the right place for "Alt+h" could be the "Tip of the
day" window. There, there is more room to write how it works.
If possible, the first time Cinelerra-GG is run the "Tip of the day"
window should show the "Alt+h" for help.
So, the new User can see it and remember (I hope) if She/He needs it.