Index: branches/5.2.x/core/admin_templates/js/form_controls.js
===================================================================
diff -u -N -r14244 -r15858
--- branches/5.2.x/core/admin_templates/js/form_controls.js	(.../form_controls.js)	(revision 14244)
+++ branches/5.2.x/core/admin_templates/js/form_controls.js	(.../form_controls.js)	(revision 15858)
@@ -90,10 +90,10 @@
 
 		case 'radio':
 			if ($value === null) {
-				$("input[name='" + jq(this.FieldMask.replace('#FIELD_NAME#', $field)) + "']:checked").attr('checked', '').change();
+				$("input[name='" + jq(this.FieldMask.replace('#FIELD_NAME#', $field)) + "']:checked").prop('checked', false).change();
 			}
 			else {
-				$( this.getControl($field, $value) ).attr('checked', 'checked').change();
+				$( this.getControl($field, $value) ).prop('checked', true).change();
 			}
 			break;