Why does File>Create>Buttons>Round Buttons cause 3 buttons in three separate files to be generated?

In GIMP 2.8, when I invoke the command File>Create>Buttons>Round Button, and click OK then 3 buttons are generated in three separate files. I am unable to understand this behaviour or to restrict to producing just one button. Interestingly, the option for "Simple Beveled Button" works just fine. Kindly help and avise please...

PS: Under the "Related Content" text box I note talk of three buttons but I can't say I understood it. Sorry. I am very new to GIMP