You can add extra funtionality to LibX through the user preferences. This includes adding LibX options to the browser's context menu (access by Right-click on PC, Control-click on Mac).
Click the LibX button then Preferences to bring up the mu
Click on Context Menu to see options. Select the check boxes of those you want to see in your browser's context menu.
You can now highlight text on a web page, right click or control click, and then search for that text.