Text input on TableWidget doesn't work well with japanese layout on Mac OS

On Mac OS X 10.7.4.1, the text input in TableWidget doesn't work correctly when using Japanese (hiragana) keyboard layout.

If I start editing a cell by directly typing what I want to enter in it, the first character isn't recognized as part of a kanji.
On the other hand, if I start the editing by double-clicking the cell or hitting enter, all the following characters are correctly recognized.

The screenshot makes it pretty clear.