I have a kendoListBox with 12,000 items. This is connected with another kendoListBox and has draggable enabled. Each listbox item has a template applied. The listbox is inside of a modal. When I click a button to open the modal there is a 3 second delay for the modal to open. Then when I try to drag an item or click the arrow buttons to move the item to the opposite list there is another 3 second delay before anything happens. The issue occurred when I changed from a list with only a couple hundred items to this large list. I had this problem with some dropdown boxes and fixed those with virtualization but virtualization does not appear to be available or work here. How do I increase performance so that these components are usable?