Yes. Enter is just one way of ending edit and saving. Any straying away from the edit box will do the same.
Hardcore...
P.S. Different browsers may behave differently here.

It depends on your browser.
"In Firefox the DOM storage data is stored in the webappsstore.sqlite file in the profile folder".
I will collect information about other browsers and add to the tutorial.

I plan to support export/import for backup and migration (to other computer/browser).
I do not plan to allow external edit. It's simply too easy to break things that way and there is just so much effort I can devote to error checking.

ANNOUNCEMENT:
Version 2.0.1 has been released with the following features:
* Added a warning about the dangers of deleting cookies to the tutorial and home pages

Thanks for the updated version, will check it out very soon! :-)

ANNOUNCEMENT:
Version 2.0.2 has been released with the following features:
* Added behind-the-scenes support for newly-removed GOG games (the four Bohemia games are the first to be removed since MaGog launched)
* Added support for people using a decimal comma instead of a decimal point (only for input; display still uses only the decimal point)
* Added a technical addendum to the tutorial page about the location of the local storage in different browsers [suggested by phaolo]
Thank you for your suggestions. One has been implemented and is now online.

So many updates, thank you man!
And yes, a Magog import\export function will be perfect, so we don't end up restoring old info for every other site.

ANNOUNCEMENT:
Version 2.1.0 has been released with the following features:
* Added the ability to export and import your "My Fields" data for backup and transfer from browser to browser [suggested by phaolo]

Note: The import facility uses a browser feature called 'FileReader'. This feature has been in implemented in Safari only in version 6.0. Unfortunately, the last Safari version released on Windows was 5.1.7 (in 2012). I therefore cannot test the import on Safari myself. If you use Safari on Mac and would like to help by testing it yourself, please contact me for details. Thank you.

Thank you for your suggestions. One has been implemented and is now online.

A great update once again ! Now, even if I get separated from my computer for a while, I can still have the "My fields" information available without having to search around for the files. Kudos to you, mrkgnao, yet again ! :-)

Thank you for implementing them!

ANNOUNCEMENT:
Version 2.1.1 has been released with the following features:
* Added mean and total price statistics at the bottom of the Price and My Fields columns on the results page

I tried the export function on FF19, but I got a PE_ui_uz.part file instead of a myfields_DATE.magog lol
Should I try the import? (I already added info for 100 games..)

Also, can you please:
- add an option to rename the custom tags?
- make the search page remember last used filters?

Why are you using FF26 rather than the current FF30?

I will PM you my email address. Email me the file and I will look at it and tell you whether it's OK.

I already plan to do it. Probably in the upcoming week or so.

At the moment I consider this low-priority. It's a lot of work.

I don't like the new FF30 many limitations :(
Also, my pc can barely sustain this version, which is one of the lightest..

I can attach the file directly here, if there isn't any kind of security problem.
It contains strings like these: ~u_IDNUM~TAG1,TAGn~ (plus the custom tags list)

Sure, post it here if GOG allows you to (which I would be surprised).
Also add the answers to my PM questions.

It's possible by simply changing the extension to .jpg (the original was .part).

Message displayed:
Here is what will be exported:
- tags information for 98 games
- the list of available tags: owned,unwanted,wishlisted

Browser :
this same Firefox, I'm using the export function as a backup.

Checked it. The file is fine. It's just the name that is messed up.

P.S. Just out of curiosity, how did you end up with two games that are both owned and unwanted?