fix navigator displaying wrong index

related to #4998

public/src/client/topic.js

@@ -63,7 +63,7 @@ define('forum/topic', [
 
 		handleKeys();
 
-		navigator.init('[component="post/anchor"]', ajaxify.data.postcount, Topic.toTop, Topic.toBottom, Topic.navigatorCallback, Topic.calculateIndex);
+		navigator.init('[component="post"]', ajaxify.data.postcount, Topic.toTop, Topic.toBottom, Topic.navigatorCallback, Topic.calculateIndex);
 
 		handleBookmark(tid);
 

public/src/modules/navigator.js

@@ -131,8 +131,8 @@ define('navigator', ['forum/pagination', 'components'], function(pagination, com
 			}
 		});
 
-		var atTop = scrollTop === 0 && parseInt(els.first().attr('data-index'), 10) === 0,
-			nearBottom = scrollTop + windowHeight > documentHeight - 100 && parseInt(els.last().attr('data-index'), 10) === count - 1;
+		var atTop = scrollTop === 0 && parseInt(els.first().attr('data-index'), 10) === 0;
+		var nearBottom = scrollTop + windowHeight > documentHeight - 100 && parseInt(els.last().attr('data-index'), 10) === count - 1;
 
 		if (atTop) {
 			index = 1;