This article: https://docs.telerik.com/kendo-ui/knowledge-base/clear-selection-all-pages-grid
uses the undocumented property _selectedIds. If would prefer using a documented way, and since the article is rather old, maybe there is one today?
When the Kendo UI Grid is set up for persistence of the selection across all pages, the only way to delete the selection on all rows is to modify the internal collection that holds the selected IDs.
This is due to the fact that the clearSelection() or any DOM manipulations will clear the selection only on the current page.
The alternative would be to modify the pageSize of the grid to accommodate all rows, call the clearSelection() method and return back the old pageSize.
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