if it is over 500 or 1000 items, you will need to look for a hack...Crystal doesn't display that many items as is.  As I think about it, why would you torture your users to look through that many lines of items.  Isn't there some grouping to the items?  If so, you can do a cascade where they select the grouping then the items.  If you displaying all the items to help them (since the obviously don't know what they are looking for...or you wouldn't need to display them all) why not go an extra step or two and help them narrow down what they don't know, or speed the finding of what they do.