TYPO3 Core

The interface is very un-intuitive here, see this example:

Go to form wizard, tab Options, and modify a text or numeric value under e.g. Label properties or Attributes properties.
After modifying, a green check mark appears at the end of the field, which suggests your input is valid.

Now press save and close, or just save and click around to another field. Your changes are gone.
The changes apparently only get saved if you click the green mark at the end of the field (!)

Please remove this 'feature' for better usability (you can always revert your changes by simply not saving).