Make this addon work on "tabs" (context menu of tabs)

[GJRobert]

Is it possible to add the menu item of this addon to the context menu of "tabs" (not the webpage HTML of tabs, rather the XUL component "tabs" themselves)? Right now, the menu of this addon only appears in the context menu of webpages. Some webpages, however, prevent context menus from displaying, thus making this addon unavailable to those.