you can save the form, open it in designer & check the javascript -
Edit: just checked myself.. on click of each checkbox, they are setting each of the other checkboxes to their Off value (0 in this case which is also the default I think)
This is the script on Checkbox of name Type_Box_1 - As you can see, they are setting all checkboxes to zero apart from the one the user will click: (Type_Box_01 is missing from the following)
Type.Type_Box_02.rawValue =
Type.Type_Box_03.rawValue =
Type.Type_Box_04.rawValue =
Type.Type_Box_05.rawValue =
Type.Type_Box_06.rawValue =
Type.Type_Box_07.rawValue =
Type.Type_Box_08.rawValue =
Type.Type_Box_09.rawValue = 0;