In general, the cascading functionality of the ComboBox, like the DropDownList, is designed to disable child widgets if parent hasn't any value. More information about the cascading feature can be found here
. The described behavior cannot be changed and in order to accomplish your goal a custom implementation will be required. Here is a Dojo demo
, that shows how to use change events of the widgets to perform data source filtration and disable/enable child widgets. You can use this approach as a starting point to implement your specific business logic.
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