move focus to poll panel when open

bigbluebutton-html5/imports/ui/components/poll/component.jsx

@@ -6,6 +6,7 @@ import { withModalMounter } from '/imports/ui/components/modal/service';
 import _ from 'lodash';
 import { Session } from 'meteor/session';
 import Button from '/imports/ui/components/button/component';
+import { findDOMNode } from 'react-dom';
 import LiveResult from './live-result/component';
 import { styles } from './styles.scss';
 
@@ -107,6 +108,10 @@ class Poll extends Component {
     this.handleBackClick = this.handleBackClick.bind(this);
   }
 
+  componentDidMount() {
+    findDOMNode(this.hideBtn).focus();
+  }
+
   componentDidUpdate() {
     const { currentUser } = this.props;
 
@@ -321,6 +326,7 @@ class Poll extends Component {
       <div>
         <header className={styles.header}>
           <Button
+            ref={(node) => { this.hideBtn = node; }}
             tabIndex={0}
             label={intl.formatMessage(intlMessages.pollPaneTitle)}
             icon="left_arrow"