FEATURE: stage post in stream on edit

app/assets/javascripts/discourse/lib/transform-post.js.es6

@@ -113,6 +113,7 @@ export default function transformPost(currentUser, site, post, prevPost, nextPos
   postAtts.actionCodeWho = post.action_code_who;
   postAtts.userCustomFields = post.user_custom_fields;
   postAtts.topicUrl = topic.get('url');
+  postAtts.isSaving = post.isSaving;
 
   const showPMMap = topic.archetype === 'private_message' && post.post_number === 1;
   if (showPMMap) {

app/assets/javascripts/discourse/models/composer.js.es6

@@ -539,7 +539,7 @@ const Composer = RestModel.extend({
       cooked: this.getCookedHtml()
     };
 
-    this.set('composeState', CLOSED);
+    this.set('composeState', SAVING);
 
     var rollback = throwAjaxError(function(){
       post.set('cooked', oldCooked);
@@ -547,6 +547,8 @@ const Composer = RestModel.extend({
     });
 
     return promise.then(function() {
+      // rest model only sets props after it is saved
+      post.set("cooked", props.cooked);
       return post.save(props).then(function(result) {
         self.clearState();
         return result;

app/assets/javascripts/discourse/widgets/post.js.es6

@@ -401,7 +401,7 @@ export default createWidget('post', {
     if (attrs.cloaked) { return 'cloaked-post'; }
     const classNames = ['topic-post', 'clearfix'];
 
-    if (attrs.id === -1) { classNames.push('staged'); }
+    if (attrs.id === -1 || attrs.isSaving) { classNames.push('staged'); }
     if (attrs.selected) { classNames.push('selected'); }
     if (attrs.topicOwner) { classNames.push('topic-owner'); }
     if (attrs.hidden) { classNames.push('post-hidden'); }