The save button isn’t easily discoverable since it isn’t in the place you are looking at when you’re editing data.

It is also unclear when you need to click the save button since I don’t get a warning when changing pages/navigating away from the device to another page/closing the tab/window. In addition, the save button looks a lot like the “tabs” above. However, the tabs and Save button do different things and should not look similar (navigation vs. action).

I created a mantis for it:

We’ll have to think more about how to make this clearer. Thanks for the input.