It's applied automatically. There's no need for a save button.
It's a foible of the web interface Chris. Some stuff must be Saved, and other settings are applied without saving.
The more I use the platform, the more I understand why, even if I wouldn't have done it that way.
I'm trying to assign a user to a group of devices, but I do not see any buttons on the screen to resolve the issue. I'm running traccar in docker using the latest tag.