Look Up in Sidebar by Kebin Liu

The goal of this add-on is provide a general look up tool in Firefox sidebar.

Currently, it support look up text from Google Translate, more look up services and customize service is coming soon.

Features:
- Look up text from selection context menu
- Look up selection text immediately (when the sidebar is open)
- Support change look up service from sidebar directly
- Enable/disable look up by selection event
- Ctrl-Shift-U (Linux/Windows) / Cmd-Shift-U (macOS) for toggle look up sidebar