Form 4747 Box 7 Will Not Check

I have entered my dependents birthdate, entered that they lived with me for the entire year (correct for a child born during 2025) and entered their SSN.  All of this shows as correct under Personal Info and form 4547 reflects correct content in Part II (lines 1-6).  Yet, the form does not check box 7 nor does it let me manually check/change the settings in that box.  Grr.