This property specifies the field name used to identify the column for initial sorting. If this property and the "initial sort column" property are omitted or set to blanks, sorting is not initiated when the grid is first rendered.
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When "initial sort field" is bound and is a comma-separated list, then the grid indicates that each column in the list is sorted; in which case, Default Sort Order determines the sort direction indicated.
Multi-sort is available with Profound UI Version 6 Fix Packs after 6. 2.1.