From db869c6ce46ce40657685ea0bfb19254e79f02aa Mon Sep 17 00:00:00 2001
From: Scott Nonnenberg <scott@nonnenberg.com>
Date: Thu, 7 Sep 2017 14:23:51 -0700
Subject: [PATCH] Scroll to bottom when adding a new message (#1450)

Added a comment to try to make this easier to understand as you read it.

FREEBIE
---
 js/views/message_list_view.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/js/views/message_list_view.js b/js/views/message_list_view.js
index 2cbf46312..f39506fe3 100644
--- a/js/views/message_list_view.js
+++ b/js/views/message_list_view.js
@@ -48,7 +48,12 @@
             this.$el.scrollTop(this.scrollPosition - this.$el.outerHeight());
         },
         scrollToBottomIfNeeded: function() {
-            if (!this.atBottom()) {
+            // This is counter-intuitive. Our current bottomOffset is reflective of what
+            //   we last measured, not necessarily the current state. And this is called
+            //   after we just made a change to the DOM: inserting a message, or an image
+            //   finished loading. So if we were near the bottom before, we _need_ to be
+            //   at the bottom again. So we scroll to the bottom.
+            if (this.atBottom()) {
                 this.scrollToBottom();
             }
         },