This sample demonstrates the selection functionality of the Tree Grid using checkbox selection, To select and unselect all rows use header checkbox. To select/unselect particular row, click the desired row.
          Tree Grid mutliple selection can be achieved with help of checkbox in
          each row. To render checkbox in each Tree Grid row, you need to define
          column type as checkbox using{" "}
          columns->type property.
        
          Selection can be persisted on all the operations using{" "}
          selectionSettings-> persistSelection property. For
          persisting selection on the Tree Grid, any one of the column should be
          defined as a primary key using  columns->isPrimaryKey{" "}
          property.
        
In this demo, Tree Grid mutliple selection has been enabled with selection persistance.
More information on the checkbox selection configuration can be found in this documentation section.