Fix some scrolling issues (#6851)

webapp/components/post_view/post_body/post_body.jsx

@@ -70,7 +70,7 @@ export default class PostBody extends React.PureComponent {
         let comment = '';
         let postClass = '';
 
-        if (parentPost && this.props.parentPostUser) {
+        if (parentPost) {
             const profile = this.props.parentPostUser;
 
             let apostrophe = '';

webapp/components/post_view/post_body_additional_content.jsx

@@ -153,7 +153,7 @@ export default class PostBodyAdditionalContent extends React.PureComponent {
         }
 
         const link = Utils.extractFirstLink(this.props.post.message);
-        if (link && Utils.isFeatureEnabled(Constants.PRE_RELEASE_FEATURES.EMBED_PREVIEW)) {
+        if (link && Utils.isFeatureEnabled(Constants.PRE_RELEASE_FEATURES.EMBED_PREVIEW) && global.window.mm_config.EnableLinkPreviews === 'true') {
             return (
                 <PostAttachmentOpenGraph
                     link={link}

webapp/components/post_view/post_list.jsx

@@ -297,7 +297,6 @@ export default class PostList extends React.PureComponent {
     }
 
     handleScroll = () => {
-        this.hasScrolledToFocusedPost = true;
         this.hasScrolled = true;
         this.previousScrollTop = this.refs.postlist.scrollTop;