Make scroll on paste in RTE compatible with https://github.com/vector-im/riot-web/pull/5900

src/components/views/rooms/MessageComposerInput.js

@@ -512,7 +512,8 @@ export default class MessageComposerInput extends React.Component {
             // composer. For some reason the editor won't scroll automatically if we paste
             // blocks of text in or insert newlines.
             if (textContent.slice(selection.start).indexOf("\n") === -1) {
-                this.refs.editor.refs.editor.scrollTop = this.refs.editor.refs.editor.scrollHeight;
+                let editorRoot = this.refs.editor.refs.editor.parentNode.parentNode;
+                editorRoot.scrollTop = editorRoot.scrollHeight;
             }
         });
     }