Disable AJAX in the theme options and add this script to the question source. It will enforce the clicking of a single radio in each row and pop up an alert if rows are unanswered on submit.
Code:
<script type="text/javascript" charset="utf-8">
$(document).on('ready pjax:scriptcomplete',function(){
// Identify this question
var thisQuestion = $('#question{QID}');
// Listener on the radios
$('input:radio', thisQuestion).on('click', function(e) {
// Identify some elements/vars
var thisRow = $(this).closest('tr.answers-list');
var thisInput = $(this);
var thisName = thisInput.attr('name');
var otherInput = $('input:radio', thisRow).not('[name="'+thisName+'"]').first();
// Uncheck other radios in this row
$('input:radio', thisRow).not(thisInput).prop('checked', false);
// Fire expression manager on the unchecked radios
var otherName = otherInput.attr('name').replace('#', '_');
$('#java'+otherName).val('');
ExprMgr_process_relevance_and_tailoring('change', otherName, 'radio');
// Check for answered rows
if($('input:radio:checked', thisQuestion).length == $('tr.answers-list', thisQuestion).length) {
$(thisQuestion).removeClass('input-error');
}
});
// Interrupt the submit and check for answered rows
$('#ls-button-submit').on('click', function(e) {
if($('input:radio:checked', thisQuestion).length != $('tr.answers-list', thisQuestion).length) {
$(thisQuestion).addClass('input-error');
alert('Please answer all rows.');
e.preventDefault();
return false;
}
});
});
</script>
