input method can't be used within any text box in unity

Binary package hint: unity

input method can't be activated within those text boxes within unity.
Step to replicated:
1 Active ibus via language-support
2 re-login desktop session
3 press Super-F, and then focus into search bar, press Ctrl+Space, ibus can't be activated.
4 Open any other applications with input box, and try with ibus, input works fine.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: unity 3.6.0-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-5.32-generic 2.6.38-rc6
Uname: Linux 2.6.38-5-generic i686
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,mousepoll,vpswitch,regex,animation,snap,expo,move,compiztoolbox,place,grid,gnomecompat,wall,ezoom,workarounds,staticswitcher,resize,fade,scale,session,unityshell]
Date: Sat Mar 5 15:17:44 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110223)
ProcEnviron:
 LANGUAGE=zh_CN:en
 LANG=zh_CN.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)