Steps to Reproduce

Run fiddle
http://zkfiddle.org/sample/qohkpu/2-Smart-listbox-initial-size

Actual Result

Listbox initially loads 50 items

Expected Result

Listbox initially loads 1000 items (as defined in the preloadSize attribute)

Debug Info

With rod=true, preloadSize currently controls the number of listitems loaded during each loading cycle.
It might be better to have different attributes for Listbox ROD and Smart listbox loading.

Root Cause

Workaround

It is possible to target a number of items to load using listbox.renderItems(set<Listitem> items):

			private Set myItemsToRender = new HashSet();
			for (int i = 0; i < 1000; i++) {
				myItemsToRender.add(box.getItemAtIndex(i));
			}
			box.renderItems(myItemsToRender);