All the changes you perform in any of the dialogues is saved in real-time in the memory. For most of them, you do not need to do any confirmation.
The application cannot perform "undo" and "redo".
The changes are lost if you leave the application or if you click [Cancel].
To make your changes persistent, you need to press [OK] or [Print].
If you want to discard all changes, you need to leave the application and use the [Revert to original] function.