diff --git a/app/assets/javascripts/discourse/components/topic-timeline.js.es6 b/app/assets/javascripts/discourse/components/topic-timeline.js.es6
index a744515e4..2e7e5c096 100644
--- a/app/assets/javascripts/discourse/components/topic-timeline.js.es6
+++ b/app/assets/javascripts/discourse/components/topic-timeline.js.es6
@@ -1,5 +1,6 @@
 import MountWidget from 'discourse/components/mount-widget';
 import Docking from 'discourse/mixins/docking';
+import { observes } from 'ember-addons/ember-computed-decorators';
 
 export default MountWidget.extend(Docking, {
   widget: 'topic-timeline-container',
@@ -12,6 +13,11 @@ export default MountWidget.extend(Docking, {
              dockAt: this.dockAt };
   },
 
+  @observes('topic.highest_post_number')
+  newPostAdded() {
+    this.queueRerender(() => this.queueDockCheck());
+  },
+
   dockCheck(info) {
     if (this.get('loading')) { return; }
 
@@ -31,6 +37,7 @@ export default MountWidget.extend(Docking, {
       this.dockAt = 0;
     } else if (pos > topicBottom) {
       this.dockAt = topicBottom - timelineHeight - parentTop;
+      if (this.dockAt < 0) { this.dockAt = 0; }
     } else {
       this.dockAt = null;
     }
diff --git a/app/assets/javascripts/discourse/mixins/docking.js.es6 b/app/assets/javascripts/discourse/mixins/docking.js.es6
index e4f2d843c..ee024ed45 100644
--- a/app/assets/javascripts/discourse/mixins/docking.js.es6
+++ b/app/assets/javascripts/discourse/mixins/docking.js.es6
@@ -3,23 +3,27 @@ const helper = {
 };
 
 export default Ember.Mixin.create({
-  _dockHandler: null,
+  queueDockCheck: null,
+
+  init() {
+    this._super();
+    this.queueDockCheck = () => {
+      Ember.run.debounce(this, this.dockCheck, helper, 20);
+    };
+  },
 
   didInsertElement() {
     this._super();
 
-    // Check the dock after the current run loop since reading sizes is slow
-    this._dockHandler = () => Ember.run.next(() => this.dockCheck(helper));
-
-    $(window).bind('scroll.discourse-dock', this._dockHandler);
-    $(document).bind('touchmove.discourse-dock', this._dockHandler);
+    $(window).bind('scroll.discourse-dock', this.queueDockCheck);
+    $(document).bind('touchmove.discourse-dock', this.queueDockCheck);
 
     this.dockCheck(helper);
   },
 
   willDestroyElement() {
     this._super();
-    $(window).unbind('scroll.discourse-dock', this._dockHandler);
-    $(document).unbind('touchmove.discourse-dock', this._dockHandler);
+    $(window).unbind('scroll.discourse-dock', this.queueDockCheck);
+    $(document).unbind('touchmove.discourse-dock', this.queueDockCheck);
   }
 });