Saving, Save As, and Backups

Saving

Click Save in the toolbar, or press Ctrl+S, to save your changes back to the original file. A * after the filename in the window title shows when you have unsaved changes. Use Save As… to save to a different file, leaving the original untouched.

Automatic backups

The Backup on save checkbox in the toolbar is ticked by default. When it's on, the very first time you save in a session, the app copies the file's current on-disk contents to a sibling file named "Backup of {your file name}" before overwriting it - your safety net if something goes wrong partway through editing. Later saves in the same session don't refresh this backup again, so it always reflects the file as it was before you started editing, not a partially-edited mid-session state.

A new session will overwrite the backup file, so be sure to test your updated file between sessions, or to create your own archive of backup versions.

Unticking this checkbox removes that safety net, so a confirmation dialog explains what you're giving up before it takes effect.