Keystroke: Ctrl + F4
If you have NOT changed the content of a file, it simply closes. Otherwise, the above dialog appears to allow you to save your changes. It contains the buttons, Yes, No, and Cancel:
Yes (or y): Your document changes will be saved. If your document has not previously been saved, then you will be shown a second dialog box to prompt you for a file name.
No (or n): Any changes you have made will be discarded.
Cancel (or c): This choice will take you back to the editing screen.