Cannot read property 'inEditor' of undefined

In our add-on it's use this method XF.focusEditor() then got these errors:

Code:

Code:

Uncaught TypeError: Cannot read property 'inEditor' of undefined
    at Object.restoreMaintainedSelection (editor.js?_v=a7fbff69:1883)
    at Object.focus (editor.js?_v=a7fbff69:1902)
    at fn.focus (editor.js?_v=a7fbff69:668)
    at fn.scrollToCursor (editor.js?_v=a7fbff69:1354)
    at Object.focusEditor (core.js?_v=a7fbff69:2902)
    at...

...

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source https://xfworld.net/threads/cannot-read-property-ineditor-of-undefined.47913/