This is expected behavior ...
... from a currently saved and applied set of network settings, if you make changes they are not immediately applied - to avoid being stuck in the middle of a multi-settings change - then you have 2 options :
- "Apply Configuration" if you think you did not miss something
- "Revert" to cancel any unapplied change, when you are unsure of for any reason to keep the currently working settings
Hope it helps !