Could you please confirm if you need to have cascading functionality in a Grid with 'incell' or 'inline' edit mode?
The cascading functionality of the DropDownList widgets is available only if the two widgets are initialized and visible at the same time. The InCell editing of the Grid allows for the editing of a single cell at a time. Therefore, when the cell is opened for editing and the DropDownList tries to find the other widget from which it should cascade, it will not find it because it is not initialized. Therefore, the cascading would not work. Thus, to achieve cascading functionality when the editable mode is configured to 'incell' you will need to filter the widgets manually.
I would suggest you take a look at the Knowledge base article linked below where cascading DropDownLists in Grid with Inline editing mode is demonstrated.
I hope you will find the provided information helpful.
Regards,
Neli
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