VBA - Runtime Error when clicking out of rich text field on ms-word

Not super familiar with VBA, so I feel like this may be a fairly simplistic question, but I can't find a resolution for my issue.

In ms-word, I've made a form in which initially, I wanted specific aspects of the form to hide/display based on different interactions with the form (code down below), which, with some help from another post, works fine, but now I've added text-fields which is causing run-time errors.

Now my issue is that the ContentControlOnExit function is being applied to when a user clicks out of a text field, which I only wanted to apply to when a user clicks out of a chechkbox, which is causing run-time error's.

Private Sub Document_ContentControlOnExit(ByVal ContentControl As ContentControl, Cancel As Boolean)

    Dim bChecked As Boolean
    bChecked = (ContentControl.Checked = True)

    If ContentControl.Title = "checkbox1" Then
        ActiveDocument.Bookmarks("approve").Range.Font.Hidden = bChecked
    End If

    If ContentControl.Title = "checkbox2" Then
        ActiveDocument.Bookmarks("sign1").Range.Font.Hidden = bChecked
        ActiveDocument.Bookmarks("sign2").Range.Font.Hidden = bChecked
    End If

    If ContentControl.Title = "checkbox3" Then
        ActiveDocument.Bookmarks("note").Range.Font.Hidden = bChecked
    End If

End Sub

Is there any simple statement I can add so that it doesn't do this check when clicking out of a text-field?