always setting app.previousUrl now, and passing cid into filter:category.topics.get hook

public/src/ajaxify.js

@@ -67,9 +67,7 @@ $(document).ready(function () {
 			apiXHR.abort();
 		}
 
-		if (!window.location.pathname.match(/\/(403|404)$/g)) {
+		app.previousUrl = window.location.href;
-			app.previousUrl = window.location.href;
-		}
 
 		url = ajaxify.start(url);
 

src/categories/topics.js

@@ -28,7 +28,7 @@ module.exports = function (Categories) {
 					topics[i].index = data.start + i;
 				}
 
-				plugins.fireHook('filter:category.topics.get', {topics: topics, uid: data.uid}, next);
+				plugins.fireHook('filter:category.topics.get', {cid: data.cid, topics: topics, uid: data.uid}, next);
 			},
 			function (results, next) {
 				next(null, {topics: results.topics, nextStart: data.stop + 1});

src/topics/tools.js

@@ -272,7 +272,7 @@ module.exports = function (Topics) {
 				db.sortedSetsRemove([
 					'cid:' + topicData.cid + ':tids',
 					'cid:' + topicData.cid + ':tids:pinned',
-					'cid:' + topicData.cid + ':tids:posts'
+					'cid:' + topicData.cid + ':tids:posts'	// post count
 				], tid, next);
 			},
 			function (next) {