Index: branches/5.2.x/core/admin_templates/js/script.js
===================================================================
diff -u -N -r15593 -r15858
--- branches/5.2.x/core/admin_templates/js/script.js	(.../script.js)	(revision 15593)
+++ branches/5.2.x/core/admin_templates/js/script.js	(.../script.js)	(revision 15858)
@@ -1876,19 +1876,19 @@
 			var $category_id = parseInt($me.attr('value'));
 
 			if ( !in_array($category_id, $allowed_categories) ) {
-				if ( $me.attr('selected') ) {
+				if ( $me.prop('selected') ) {
 					$selected_category = $me;
 				}
 
-				$me.attr('disabled', 'disabled');
+				$me.prop('disabled', true);
 			}
 		}
 	);
 
 	if ( $selected_category !== false && $allowed_categories.length > 0 ) {
 		// when selected category became disabled -> select 1st available category
-		$selected_category.attr('selected', '');
-		$("option[value='" + $allowed_categories[0] + '"]', $categories).attr('selected', 'selected');
+		$selected_category.prop('selected', false);
+		$("option[value='" + $allowed_categories[0] + '"]', $categories).prop('selected', true);
 	}
 }