+ the Window is referenced before the widget is initialized on the page
+ the Window is referenced after the widget has been destroyed
+ a second jQuery instance is registered on the page after the Kendo UI scripts, which deletes all Kendo UI widgets
Judging by the provided information, I would exclude the first option, so please focus on the other two. To begin with, you can debug the script and check whether $("#window") returns the expected DOM element.
In case you need further assistance, please provide a runnable demo.
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