Why does a empty field come up on Gift registry?

Hello, I am trying to enter just one class for selection using Gift Registry. A empty filed comes up below it. Why? please help me get ride of it. i don't need people checking that box by mistake.

Can you please confirm if this is your form http://www.jotformpro.com/form/52309088505961 that was having the issue? I checked and test the form, but I could not seem to reproduce the issue you described.

Could it be you had resolve it already? Please let us know if issue persist.