Very nice Rated 4 out of 5 stars

Apart from the very irritating restart popup message that appears in the address bar, the addon is very cool. It's a pretty nice descendant of an older similar addon.

My suggestions:
- Make the restart popup appear where the toolbar icon is (if visible) and not on the start of the addressbar.
- Make the restart popup window disappear after a configurable timeout (3-5 seconds would be nice as default) and NEVER appear again, unless another addon is updated. It's extremely irritating to stop your work to close the popup, only for it to appear everytime you open/close a new tab. OK, i updated my addons, i DO NOT want to restart, period. No need to be reminded every 5 seconds.
- Time between checks could also contain a "3 hours" period. For those people working 8 hrs a day, it may be convenient to check twice a day for new addons.

This review is for a previous version of the add-on (2.1). 

The built-in popup mechanism will only open at the start of the address bar. I have seen other extensions that use something that looks similar, but they make the popup internally to their extension. I'm not going to do that. There is also no way to hide the door hanger automatically without also hiding the icon, so I don't want to add that either. However, there is a "hidden" setting you might want to activate (it will probably make it into the options page someday.) Enter about:config in the address bar and search for extensions.UpdateAddon.LessAggressive . Double-click to set it to true. The popup will stop coming back on tab selection. If you don't want to do that, you could also select "Hide this notification" from the drop down in the popup itself (the arrow next to "Install updates"), but you have to do that every time you get an update. While you are in the about:config, you can also select 3 hours between checks. Set extensions.UpdateAddon.CheckTime to 3 . I have looked into making the drop down in the options panel an input box as well, but so far I haven't came up with a way I like that has the drop downs and allows input. Maybe in a future version though.