Choosing an entry from the drop-down list of kanji alternatives puts the text cursor in the wrong place when entering Japanese text in a QTextEdit

To reproduce (Mac only):

1. Run the text edit section of the Qt demo app on Mac OS X (or use any QTextEdit)
2. Select Japanese Hiragana input method
3. Type some text (eg. "yamaha")
4. Press Space to change to another candidate in the IME

EXPECTED: The text should change, but the cursor should remain at the right-hand end of the text.
ACTUAL: The text changes, but the cursor moves to the left of the text you've input.

5. Press Return to accept the current candidate

EXPECTED: You should be able to carry on typing.
ACTUAL: You can't, because the cursor is at the left of the text.

Note: I tried applying the patch for QTBUG-2064, which is useful but does not fix this problem.