[Plugin: NextGEN Gallery] NExt Gen watermark

Can anyone tell me, working with the Next Gen gallery and it’s watermark feature, whether this message :

Please note : You can only activate the watermark under -> Manage Gallery . This action cannot be undone.

means that once you’ve activated the watermark feature in one gallery it remains an un-doable feature for that gallery or that you have to use the watermark forever more on all galleries ?

It’s just not clear to me and I don’t want the watermark on every gallery, just the ones that I choose.

http://wordpress.org/extend/plugins/nextgen-gallery/