Uncaught TypeError: Cannot read property 'focus' of undefined
    at constructor._onTabChange (ConfigurableFormPanel.js:934)
    at constructor.fire (ext-all-debug.js:20326)
    at constructor.doFireEvent (ext-all-debug.js:21244)
    at constructor.doFireEvent (ext-all-debug.js:65377)
    at constructor.prototype.doFireEvent (ext-all-debug.js:55078)
    at constructor.fireEventArgs (ext-all-debug.js:21097)
    at constructor.fireEvent (ext-all-debug.js:21056)
    at constructor.setActiveTab (ext-all-debug.js:231687)
    at constructor.doActivateTab (ext-all-debug.js:231119)
    at constructor.onClick (ext-all-debug.js:231099)