On Mac with current trunk, the <option> key is not recognized for any keybindings. (The Mac standard is for <option>-[arrow key] to move the cursor around by words/paragraphs, so this is a real problem.)
Opening up the shortcuts preferences dialog, I find that all keybindings that previously were assigned to <option> now indicate that they are assigned to <control> instead (going by the symbol displayed in the dialog); however, the <control> key is ignored as well. Moreover, it is not possible to change the keybindings back to <option> using the dialog: trying to assign <option><left> to word-left results in just the <left> key registering in the dialog. Note: the <option> key is also used to enter accents and other non-standard characters; this use is not affected. It's only LyX's keybindings that ignore <option>. BH
