add editor container class.

lib/components/Editor/index.js

@@ -272,7 +272,7 @@ var Editor = function (_React$Component) {
       var inputValue = value || this.state.value;
       return _react2.default.createElement(
         "div",
-        null,
+        { className: "comment-editor-container" },
         _react2.default.createElement(
           "div",
           {

src/components/Editor/index.js

@@ -173,7 +173,7 @@ class Editor extends React.Component {
       (!this.props.value && !this.state.value && !this.state.fileList.length);
     const inputValue = value || this.state.value;
     return (
-      <div>
+      <div className="comment-editor-container">
         <div
           className={classnames({
             "comment-editor-toolbar": true,