Rated 3 out of 5 stars
1. Doesn't respect "browser.search.context.loadInBackground" about:config pref. https://bugzilla.mozilla.org/show_bug.cgi?id=727131
2. Left click should respect "browser.search.openintab" pref (which is false, by default, btw) and in case it's false - it should search for the selection in the current tab.
3. Context menu item is hidden for some reason, when rightclicking a selection in the textarea.