ServerComm.js:856 Uncaught TypeError: Cannot read property 'appendChild' of null
    at constructor.appendNodes (ext-all-debug.js:77345)
    at constructor.doAdd (ext-all-debug.js:77352)
    at constructor.callParent (ext-all-debug.js:7036)
    at constructor.doAdd (ext-all-debug.js:105093)
    at constructor.onRangeFetched (ext-all-debug.js:95688)
    at constructor.renderRange (ext-all-debug.js:95640)
    at constructor.callback (ext-all-debug.js:95464)
    at constructor.getRange (ext-all-debug.js:35809)
    at constructor.scrollTo (ext-all-debug.js:95463)
    at constructor.doEnsureVisible (ext-all-debug.js:84401)