The following two methods for trying to programatically remove an item from a kendo dropdownlist were taken directly from Kendo forums but did not work. Both methods caused the dropdownlist to vanish entirely from the UI. The dropdownlist is defined in the header of a kendo grid control. I have verified that the _selectedLoosePartIndex value is good. Have to say that so far this product has cost me weeks of additional programing time trying to do the most simple tasks imaginable. I have no idea why it is such a popular product. I really do not believe that you guys have even attempted to thoroughly test the API in real world applications.
//Method one:
var data = $('#AvailableLooseParts').kendoDropDownList().data("kendoDropDownList").dataSource.data();
data = data.splice(_selectedLoosePartIndex, 1);
$('#AvailableLooseParts').kendoDropDownList().data("kendoDropDownList").dataSource.data(data);
// Method two:
var ddl = $('#AvailableLooseParts').data("kendoDropDownList");
var itemToRemove = ddl.dataSource.at(_selectedLoosePartIndex);
ddl.dataSource.remove(itemToRemove);
ddl.select(0);