I have a List with several columns, and I created a new Form from this List and chose to display just a few of the List columns in the Form. I now need to add additional columns from the List to the existing Form. However, the Show or hide fields section in the Form only displays the columns from the List that are already in the form - none of the other columns in the List are displayed in the Show or hide fields section in the Form so I can't add them to the Form. When I create a new Form, I have the same issue with only a few of the List columns showing in the Show or hide fields section in the Form. When I click Add new item, everything is fine but we need to use a form, not this option.
These are the columns in the List.

This is the Form - note only three columns from the List are visible - the other columns in the List are not displayed.
