In order to achieve the desired functionality, you can pass a parameter to the partial view, where the combobox is nested in. When attempting to bind the ComboBox, eg when its DataSource.Read() method is triggered, you can set a value for a hidden field in the PartialView, where the combo is nested. Then, when the Data function is triggered, you can read the value of the hidden field and determine which widget initiated the binding.
In the attachment you can find a sample example on this implementation.
Note: scripts and packages are removed from the attachment, due to file upload limit.
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