https://www.telerik.com/forums/how-to-disable-hide-the-navigation-buttons-after-selecting-show-all-in-radgrid-paging
I've added the "ALL" option to the PageSizeComboBox in RadGrid. Very similar to this option: http://www.telerik.com/community/forums/aspnet/grid/how-to-...
how todisablehidenavigationbuttons