Prefer import React, set prevEvent to last MemberhsipChange

src/components/structures/MessagePanel.js

@@ -328,7 +328,8 @@ module.exports = React.createClass({
                         {eventTiles}
                     </MemberEventListSummary>
                 );
-                prevEvent = mxEv;
+                // Set previous event to last MembershipChange
+                prevEvent = this.props.events[i - 1];
                 continue;
             }
 

src/components/views/elements/MemberEventListSummary.js

@@ -13,7 +13,7 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
-const React = require('react');
+import React from 'react';
 const MemberAvatar = require('../avatars/MemberAvatar.js');
 const dispatcher = require("../../../dispatcher");