When multicolumn sorting is disallowed, the control would only allow sorting for one column. For example, if you sort on CustomerID, the column will be sorted accordingly.
Then, if you sort on another column, the sorting will be removed from the other column, and the new column will be sorted as needed.
On the other hand, with multi column sorting allowed, one can sort many columns, and sorting each subsequent column will not remove the sorting on the previous one(s).
I hope this information makes sense. Let me know if I am leaving something out.
the Telerik team
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