As far as I tried, this was reproducible only with java/awt/im/IMFTest and wasn't reproducible with Notepad demo.

Since jdk7-b15, IM-selection from System menu doesn't work on Windows and Solaris.

On Windows Vista, the list of InputMethods which can be selected is displayed correctly after "Select InputMethod" menu item in System menu is clicked. But you cannot choose any of them. Your choice will be ignored in IMFTest, irrespective of the InputMethod's type (native of Java).

On Solaris 10, the list of InuptMethods is NOT displayed even if you click "Select InputMethod" menu item. Instaed, a gray plain rectangle is displayed for a quick moment.

# How to reproduce
What I did were:
  - Copy two InputMedhod (CityIM.jar and CodePointIM.jar) to jre/lib/ext.
      (CityIM can be found in test directory, CodePoint IM in demo/jfc.)
  - Make some System-based InputMethods available.
  - Try to switch above InputMethods via "Select InputMethod" menu item in System menu.

Note: IM-switching from System's language bar/menu works correctly. Only IM-switching via System menu looks broken.
I contacted ###@###.###. The exact version of Solaris is 10 (x86). The window manager is CDE. He thinks that the problem on Solaris can be ignored because it appears only under Motif Look and Feel, which is not supported in JDK7.
Copied form the description of 6663665:
When input method selection popup appear, InputMethodDescriptor.getAvailableLocales() is being called repeadedly and sometimes interfere with user operation.
In order to reproduce,
place attaced WuBi.jar in jre/lib/ext.
lanunch Notepad demo.
from system menu click Select Input Method.
try to select wubi or Test input method.
You should notice following trace messages repeatedly output in console.

WuBi IM:getAvailableLocales() is being called.
Test IM:getAvailableLocales() is being called.

This doesn't happen (called once, not repeatedly many times) in 6u3.