I've applied the patch, and find out that the patch changes the inputmethod style from "off the spot"(current default inputmethod style of lyx1.5.0beta1) to "on the spot". Other than that, I cannot see any difference up to now.
Cghan, Thank you for your test.
Mr. Iwami, can you tell us what else we can test for your patch? Anyway, I would like to welcome you for a much needed lyx-developer who is a native CJK language user, right?
This is a patch like your point that changes the input method style to "On the spot". But the preedit character string was not able to be displayed even by "Off the spot" in my environment (LyX1.5svn, Windows, Japanese, and Qt4.2.2) and this patch was made because it was no use. And it developed with Japanese and Windows, and I wanted to learn whether to use it with other languages and OS. After that, I want the idea that does this implement smarter. -- M. Iwami