Fix channel creation errors

web/react/components/channel_notifications_modal.jsx

@@ -32,11 +32,13 @@ export default class ChannelNotificationsModal extends React.Component {
             activeSection: ''
         };
     }
-    componentDidMount() {
+    componentWillReceiveProps(nextProps) {
-        ChannelStore.addChangeListener(this.onListenerChange);
+        if (nextProps.show) {
-    }
+            this.onListenerChange();
-    componentWillUnmount() {
+            ChannelStore.addChangeListener(this.onListenerChange);
-        ChannelStore.removeChangeListener(this.onListenerChange);
+        } else {
+            ChannelStore.removeChangeListener(this.onListenerChange);
+        }
     }
     onListenerChange() {
         const curChannelId = ChannelStore.getCurrentId();