Gb2Big is a handy translator between simplified and traditional Chinese.
Use CN Flag for Simplified Chinese
Use HK Flag for Traditional Chinese
Use UN Flag for Online Proxy Service

To activate this add-on:
1. Right click on the toolbar
2. Select "Customize..." from the popup menu
3. Now the "Customize Toolbar" dialog shows up
4. Drag and drop the flag button from the dialog onto the toolbar

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