ServerComm.js:856 Uncaught TypeError: Cannot read property 'isVisible' of null
    at constructor.onChildNodesAvailable (ext-all-debug.js:46812)
    at Object.callback (ext-all-debug.js:5441)
    at constructor.onChildNodesAvailable (ext-all-debug.js:47463)
    at Object.callback (ext-all-debug.js:5441)
    at constructor.onProxyLoad (ext-all-debug.js:47915)
    at constructor.triggerCallbacks (ext-all-debug.js:36250)
    at constructor.setCompleted (ext-all-debug.js:36232)
    at constructor.setSuccessful (ext-all-debug.js:36239)
    at constructor.process (ext-all-debug.js:36192)
    at constructor.processResponse (ext-all-debug.js:39162)