message: don't need this as we prevent unneeded updates in shouldComponentUpdate
diff: @@ -161,7 +161,7 @@ module.exports = React.createClass({
  calculateUrlPreview: function() {
  //console.log("calculateUrlPreview: ShowUrlPreview for %s is %s", this.props.mxEvent.getId(), this.props.showUrlPreview);
  - if (this.props.showUrlPreview && !this.state.links.length) {
  + if (this.props.showUrlPreview) {
  let links = this.findLinks(this.refs.content.children);
  if (links.length) {
  // de-dup the links (but preserve ordering)
  