better check for pinned

public/src/forum/category.js

@@ -191,8 +191,8 @@ define(['composer', 'forum/pagination', 'share', 'navigator', 'forum/categoryToo
 
 				if (numTopics > 0) {
 					for (var x = 0; x < numTopics; x++) {
-						var pin = $(topics[x]).find('.fa-thumb-tack');
-						if (pin.length && !pin.hasClass('hide')) {
+						var pinned = $(topics[x]).hasClass('pinned');
+						if (pinned) {
 							if(x === numTopics - 1) {
 								topic.insertAfter(topics[x]);
 							}