It is relevant, but in my mind the text describes a "state" rather than an "action", which is why I chose "None" rather than "Un-mark".
In English, "Label" and "Mark" can be noun or verb (meaning "to label" or "to mark"), depending on either the context or the readers interpretation
In the case of this tool, it's ambiguous, and is in the mind of the beholder, hence your question, and my emphasis on "in my mind".
Because of this ambiguity, in the English version, my choice of "None" versus "Un-mark", was partly designed to remove the ambiguity inherent in the other 2 buttons so that they would be interpreted as DESCRIPTORS, rather than VERBS in the mind of the user. (This is also a good reason to use the plural forms "Labels" and "Marks", as they are clearly NOT verbs. )
Hi! This part was lacking when I've replied. Then, if they are nouns:
Labels = Etichette
Marks = Marcatori (markers, the only suited translating noun for "marks", being "marche/i" concerning brands, logo and fiscal matters)
None = Nulla (nothing) being "none" = "nessuno"
The questions are the same like in French above:
Che cosa (tu) mostri? - (delle) etichette (what do you show? - labels)
Che cosa (tu) mostri? - (dei) marcatori (what do you show? - marks)
Che cosa (tu) mostri? - nulla (nothing, being the reply "nessuno" grammatically uncorrect; If you answer "nessuno" the question would be: quanti (tu) ne mostri? (how many do you show?)