Have you met the case that Emacs in iterm2 on Mac does not recognize M-S-RET
(Meta(Option)+Shift+ Return key)? I guess it's related to the modifier key conversions in terminals.
M-S-RET
is used in org-mode
I tried describe-key
in Emacs and got M-[1 3; 4
I think M
stands for meta, 13 is the ASCII code of return
, 4 is the CSI u code for Shift+Alt
see http://www.leonerd.org.uk/hacks/fixterms/