Using Org-mode, it was incredibly inconvenient when both in FreeBSD and Linux, Alt-Enter, or Alt-Return as XTerm calls it, stole the Alt-Return key combination and just maximised itself.
Not sure if this is i3wm related, but could just be that other window managers re-configure this.
I can’t remember how I fixed this in Linux a few years back, but just had to go through it all again in FreeBSD with i3. XTerm reads .Xdefaults, and adding the following to the bottom fixed it:
*VT100.Translations: #override \
Alt <Key>Return: \n\There are Google hits claiming XTerm*fullscreen: never or XTerm*omitTranslation: fullscreen fixes it, but that was not the case for me.
Hope this gets you back using Org-mode!