problem

JS Exception Uncaught TypeError: Cannot read property 'isModel' of null is triggered.

The user gets a rootcause input window, but can proceed work.

steps to reproduce

1. expand the file panel
2. select a segment
3. click on the empty space under the filetree

exception trace

ext-all-debug.js:197303 Uncaught TypeError: Cannot read property 'isModel' of null
at constructor.setRow (ext-all-debug.js:197303)
at constructor.getDefaultFocusPosition (ext-all-debug.js:204628)
at constructor.onFocusEnter (ext-all-debug.js:204369)
at constructor.onGlobalFocus (ext-all-debug.js:27515)
at constructor.fire (ext-all-debug.js:20731)
at constructor.doFireEvent (ext-all-debug.js:21700)
at constructor.prototype.doFireEvent (ext-all-debug.js:58105)
at constructor.fireEventArgs (ext-all-debug.js:21553)
at constructor.fireEvent (ext-all-debug.js:21512)
at constructor.processFocusIn (ext-all-debug.js:122339)

exception trace

Same trace but with message:
"row is null"

solution

Since the issues comes up more often, implement a workaround?
Or wait for the next extjs update.