After using "Chinese - Pinyin" in Ubuntu 12.04 for a while， it becomes impossible to switch to English, as it doesn't respond to clicking "Input method -off" or to hitting Shift key. Clicking "Restart" doesn't restart it either.
After another while, the input method doesn't allow input Chinese either, and its icon even disappear from the pannel on the up right corner.
I wonder how to solve this problem? Thanks!