Hello,
we are using Kendo UI for angular and dicsovered that multiselect does not work unless user clicks on checkboxes (even if checkboxOnly is set to false). Its reliably reproducible even on your sameple in documentation: http://www.telerik.com/kendo-angular-ui/components/grid/selection/#toc-selection
There if selection mode is 'mutiple' clicking on rows (not checkboxes) only allows single row to be selected at the time.
Jan