Chrome (37) throws error in WYMeditor.editor.prototype._isPOrDivAfterEnterInEmptynestedLi

Reproduce:
Visit src/test/advanced.html in your browser. Click in the list container of the first sample WYM editor.  Press enter twice to create a new container.  Error in console: `Uncaught TypeError: Cannot read property 'tagName' of null`

See line 2400 of base.js