I've can change the size of the main checkbox dropdown, but I can't figure out how to change the size of the autocomplete dropdown. Here's what I've tried, along with a bunch of other stuff:
var itemWidth = 200;
var itemHeight = 36;
radCheckedDropDownList1.AutoCompleteMode = AutoCompleteMode.Suggest;
radCheckedDropDownList1.DropDownListElement.AutoCompleteSuggest.SuggestMode = SuggestMode.Contains;
radCheckedDropDownList1.DropDownListElement.ListElement.ItemHeight = itemHeight;
radCheckedDropDownList1.DropDownMinSize = new Size(itemWidth, (people.Count * itemHeight) + itemHeight);
radCheckedDropDownList1.DropDownMaxSize = new Size(itemWidth, (people.Count * itemHeight) + itemHeight);
radCheckedDropDownList1.DropDownMaxSize = new Size(itemWidth, (people.Count * itemHeight) + itemHeight);
RadCheckedAutoCompleteBoxListElement autoCompleteList = radCheckedDropDownList1.CheckedDropDownListElement.AutoCompleteEditableAreaElement.AutoCompleteTextBox.ListElement as RadCheckedAutoCompleteBoxListElement;
autoCompleteList.ItemHeight = itemHeight;
radCheckedDropDownList1.DropDownListElement.AutoCompleteSuggest.DropDownList.DropDownSizingMode = SizingMode.None;
radCheckedDropDownList1.DropDownListElement.AutoCompleteSuggest.DropDownList.DropDownMinSize = new Size(itemWidth, 400);
radCheckedDropDownList1.DropDownListElement.AutoCompleteSuggest.DropDownList.DropDownMaxSize = new Size(itemWidth, 400);