I don't know if this is an Apple problem or a Firefox problem, to be perfectly honest. It used to be, if I had a window open on my Macbook air and I looked at my iPhone, the the Firefox browser would appear in the app bar with a little icon on the top right of it indicating it was the window currently open on my desktop. It hasn't been doing this anymore. It still does it between my phone and iPad, but never between my phone and my desktop. I checked and all my devices are still connected and synced to the same account. Why isn't it working and what can I do to get that feature working again between my phone and desktop?