I have a custom form with many checkboxes. One of them is behaving such that once the form is published, the checkbox unchecked, then when I check it, instead of a black check that I can turn on/off, it's grey and I can't uncheck it. I believe there I was able to attach a screenshot of the checkbox Properties (below). Any suggestions on what I can do to make this rogue checkbox act the same way as all the other check boxes?