Rated 4 out of 5 stars

Cool extension for Firefox and Thunderbird. But:
- On Linux (Ubuntu & Fedora Gnome 3) I don't see Icon con system tray (Although Thunderbird and Firefox still run)
- On Windows 10, it is not only 1 icon if have more than 1 Windows, please add feature for only 1 icon on system tray, and Exit items for each windows when right click on the icon.
Thank,