The grouping in the Grid is by matching values. Since null
and empty string
are different values, it is by design to have different groups.
I can suggest checking if the null values are correctly converted to an empty string in the Grid data. If client-side grouping is performed, and the data cannot be converted server-side, it is possible to do that client-side, in the schema.parse function:
You can verify if the data is properly converted server-side by inspecting the server-response.
If you notice an erroneous behavior in Kendo UI and further assistance is needed, please send a runnable example, so we can investigate it.
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