Comment 5 for bug 1761606

Since the older bug (1685502) was marked duplicate in favor of this one, I'll just copy a few related links (aside from the listed duplicates) that might be of interest:

https://bugs.launchpad.net/ubuntu/+source/network-manager-applet/+bug/938380
https://bugs.launchpad.net/ubuntu/+source/network-manager-applet/+bug/1652454
https://bugs.launchpad.net/ubuntu/+source/mate-panel/+bug/1675580
https://ubuntu-mate.community/t/17-04-nm-applet-works-fine-but-shows-2-icons-in-the-system-tray/12020/22
https://github.com/mate-desktop/mate-panel/issues/539

Would be nice to finally see this fixed across all Ubuntu flavors, but maybe that's not possible due to different approaches (panels).