Input mode does not change if input method is chosen from system and later changed to java

To reproduce bug follow steps below..

1) Copy im jars from jre/lib/im to jre/lib/ext
2) Configure windows to have Thai layout
3) Launch Notepad demo
4) Select "Thai" from "System Input Methods"
5) Type characters in textfield, input will be in thai
6) Now select "Devanagari Input Method" from menu (Java)
7) Type characters in textfield, input will still be in thai
8) Input method is not changing to "Devanagari Input Method"

Screen shot attached..
The bug is seen in Windows XP. Its reproducible with Tiger as well.
Thai layout is specified just as an example. This can be reproducible by choosing any System input method and later switch back to Java input method. Once system input method is selected, even if we select a Java input method, there is no change in input mode. But the Popup menu will show the Java input method as selected.

In WinXP, system input methods are added from "Regional and Language Options" -> "Text Services and Input Languages".
Tried on jdk1.4.1, its still reproducible on WinXP.
This is reproducible on WinXP, I tried on three different WinXP machines.

This is not specific to any input method, in newly attached screenshot I'm selected the System Input Method as Russian, typed lots of characters. Then switched to Devanagiri in Java input method. But still its typing in Russian.