This script displays a tooltip with expanded translation provided by Google Translate. The original author is Mar Cnu and the original version of this script can be found here. After Greasemonkey was updated to version 2.x, the script stopped working. So I fixed it. The only thing I modified to the script is that I have specified all @grant values inside the metadata block of this script. I have also updated the ColorPicker library to a new version.
Select a text, move the mouse over the 'translate' icon, and a tooltip with the translation appears. See image below.