From de17a8e8569d54d1bf247ed328330c1ed8d85a9d Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Wed, 29 Nov 2017 09:54:57 +0800
Subject: [PATCH] UX: Sync input and preview when user is typing.

---
 .../discourse/components/composer-editor.js.es6        | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/app/assets/javascripts/discourse/components/composer-editor.js.es6 b/app/assets/javascripts/discourse/components/composer-editor.js.es6
index f74e2e4ab9..170cf2fd11 100644
--- a/app/assets/javascripts/discourse/components/composer-editor.js.es6
+++ b/app/assets/javascripts/discourse/components/composer-editor.js.es6
@@ -137,8 +137,6 @@ export default Ember.Component.extend({
     });
 
     Ember.run.schedule("afterRender", () => {
-      $input.scrollTop(0);
-
       $input.on('touchstart mouseenter', () => {
         if (!$preview.is(":visible")) return;
         $preview.off('scroll');
@@ -146,6 +144,14 @@ export default Ember.Component.extend({
         $input.on('scroll', () => {
           this._syncScroll(this._syncEditorAndPreviewScroll, $input, $preview);
         });
+
+        $input.on('keypress', () => {
+          Ember.run.debounce(
+            this,
+            this._syncScroll, this._syncEditorAndPreviewScroll, $input, $preview,
+            200
+          );
+        });
       });
 
       $preview.on('touchstart mouseenter', () => {