Cocoa: When typing in a Korean character and then press enter, it will take two presses before the enter key is actually invoked.

If you set it up to be a Korean keyboard and then press g (on a latin1 based keyboard) then it will show that it is composing, and pressing enter will finish the compose, to get a new line you have to press it again. Based on what I could tell with native applications it should send the enter through to be processed as a normal key press too.