I'm using emacs23 on Ubuntu 32-bit 10.04/10.10 with GNOME and Compiz.
Pressing M-RET in an org-mode plain list in Emacs (GUI) inserts a new item. Pressing M-Up moves the item up in the list.
These keys don't work as expected in emacs -nw under Terminator and gnome-terminal. The M-Up key does nothing, whereas the M-RET key simply moves the cursor down one line and indents the position. The keys also don't "work" in xterm, which inserts \215 instead. Pressing ESC-RET or ESC-Up instead produces the expected functionality. The same problems exist if I run emacs -nw on a headless server accessed via ssh under Terminator, gnome-terminal and xterm.
I've searched both generally and on the org-mode Gmane list for an answer to this, but have not found anything. Is this a known issue with org-mode or is it related to the terminal emulator and/or the Window Manager?
In addition to the keys in my question, S-TAB, S-Left, S-Right, S-Up and S-Down were not working over ssh and PuTTY. Using certain keys on a TTY connection (ssh, screen, PuTTY) is a known issue.
Alternative keys are included in org-mode as detailed in 'Using Org on a TTY' in the org-mode manual.