Tested on Redhat Linux 6.1J, 6.1J update and 6.2J
with Kestrel linux beta b05;

IM menu does not appear on System Menu in both case of gnome and KDE,
therefore SPI can not work at all.

Two files are attached to reproduce,
WuBi.jar
TextAreaTest.java

To reproduce,
1. Copy WuBi.jar to jdk1.3/jre/lib/ext/.
2. Compile TextAreaTest.java
3. Launch TextAreaTest
4. See Systme menu.
You'll find that Input Method Menu does not appear on System menu.