preedit string on XIM composition is not shown

[Takano Akio]

Hi,

When I input Japanese characters to urxvt-unicode using XIM
in a certain condition, the preedit string is not shown.

I'm using rxvt-unicode v7.1, but the CVS version has the
same problem.

The system locale is ja_JP.utf8.

I can reproduce the problem with the following way:

1. start rxvt-unicode
2. enlarge the window vertically
3. put the cursor at the bottom line of the window
4. turn XIM on and type some characters

Regards,
Takano Akio