To try the thousands of add-ons available here, download Mozilla Firefox, a fast, free way to surf the Web!
CloseWelcome to Firefox Add-ons.
Choose from thousands of extra features and styles to make Firefox your own.
CloseReview for Mailbox Alert by eco-technologic.fr
Rated 5 out of 5 stars
When you choose display effect (None) AND duration NONE, alert stay visible until clicked.
I don't know if it it a bug, but it is usefull !
To create your own collections, you must have a Mozilla Add-ons account.