Good idea, but... Rated 3 out of 5 stars

Works exactly as says on W7. However, on OSX it does nothing at all. Please specify that is a Windows-only add-on. Thanks.

(Update 15 May 2014)
Mic,
Thanks for your quick reply. The problem with OSX is probably due to the fact that Thunderbird notifications are channelled through Growl. Keep up the good work,
Alexx

(Update 22 May 2014)
Growl notifications remain active even with the "make draft unread" option checked. You will need to test it again on OSX using Growl.

Ez az értékelés a kiegészítő előző verziójához készült (1.0). 

Not only for Windows

Hi Alexx,

this addon is not meant to work only on Windows. I developed it on Linux and tested on Windows and Linux and it works.
Sadly I had no way to test it on OSX, but I'm not using any system specific function. I'll find an OSX system to test it on it and verify what's happening.
Bye,
Mic