if someone had a problem with the extension, it will not work as it should suggest:
1. Press the menu button New Fx Menu and then help
2. From the Help menu, select the Information for Technical Support
3. Press the Reset Firefox in the right upper corner of the page with information for technical support.

Jason, thank you for finally jumping on the Firefox boat. I'm one of those who donated for the Chrome extension, even though I didn't really need the extra features. I was desperate to ditch Chrome but for a long time the lack of this extension on Firefox prevented me from making the switch. That's how convenient it is.

This piece of software was the only reason which prompted me to use Chrome some time ago. It's now available on Firefox which provides an even better user experience. Many thanks to the developper for thiswork and the Mozilla team for ongoing efforts necessary to facilitate the port from Chrome to Firefox. Best addon ever for me!

The only reason I was using the other browser was because of this awesome Add-ons and sadly it wasn't available on Firefox, but now I can finally use Firefox as my main browser and get to use Checker Plus for Gmail \o/ WebExtensions FTW! I love how I can do everything in one place and get notified whenever I received an email and the best part is having a unified inbox at glance! 5 stars is not enough TBH. Thanks!