"An unexpected behavior" notification when Firefox is windowless on MacOS

[edwardgalligan]

This doesn't seem to cause any actual negative side-effects (all my sessions are safe and saved and restore fine), but the notification is a little bit annoying so I decided to report this here for informational purposes.

On MacOS, the normal behaviour for all apps when you close the last window of the app is that the app process remains: the app shows as running in the Dock and the menubar at the top of the screen is still usable, but there are just no windows. This mode for Firefox seems to trigger this error in this extension.

Whenever I close the last tab in the last window of Firefox, I immediately get a repeating notification from the Sync Tabs extension (screenshot below). This notification keeps popping up persistently until I either close Firefox completely, or reopen a Firefox window.

Presumably the extension always expects there to be a Firefox window while Firefox is running. Clicking the notification does nothing, presumably for the same reason.

System details:

• MacOS Mojave
• Firefox DeveloperEdition 64.0b5

[Morikko]

This is probably a false positive. I will have a look to correct it.