updated to code to pass test

browser/components/MarkdownPreview.js

@@ -483,7 +483,10 @@ export default class MarkdownPreview extends React.Component {
     eventEmitter.on('export:save-md', this.saveAsMdHandler)
     eventEmitter.on('export:save-html', this.saveAsHtmlHandler)
     eventEmitter.on('print', this.printHandler)
-    eventEmitter.on('config-renew', this.rewriteIframe.bind(this))
+    eventEmitter.on('config-renew', () => {
+      this.markdown.updateConfig()
+      this.rewriteIframe()
+    })
   }
 
   componentWillUnmount () {

browser/lib/markdown.js

@@ -265,9 +265,9 @@ class Markdown {
     }
     // FIXME We should not depend on global variable.
     window.md = this.md
-    ee.on('config-renew', () => {
+    this.updateConfig = () => {
       config = ConfigManager.get()
-    })
+    }
   }
 
   render (content) {

tests/lib/snapshots/markdown-test.js.md

@@ -31,7 +31,7 @@ Generated by [AVA](https://ava.li).
 
     `<ul>␊
     <li class="taskListItem"><input type="checkbox" id="checkbox-2" /> Unchecked</li>␊
-    <li class="taskListItem"><input type="checkbox" checked id="checkbox-3" /> Checked</li>␊
+    <li class="taskListItem checked"><input type="checkbox" checked id="checkbox-3" /> Checked</li>␊
     </ul>␊
     `