The auto-matching algorithm for Japanese was also rewritten, I think the new code works somewhat better. (For the song I used for testing, I can just hit Enter most of the way through, more than I remember being able to with the old.)
There are some slight oddities with the way the display scrolls when the input goes too close to the edge, but while it can feel confusing it should still keep everything you want to see, visible.
Fixes#847 and #708.
Originally committed to SVN as r3032.