>Al, thanks for your reply. I think that the real problem that I am having is filtering from 40,000 items to 20 items and back. What if I used a class as a screen and loaded the other instance (20 items) when they clicked the check box?? Use a lockscreen for the switch. Kind of an optical illusion, if you will.

Sure, that should work fine. I later thought of always displaying both data sets, e.g. two lists one titled "All Items" and the other titled "My Ticket Items". I then took it a step further and thought that a classic "mover" dialog might work well - both lists side-by-side, with arrow buttons between them to let you move items from one list to the other as needed.

It sounds like you want to always have both lists "available" so you don't have to recalc them (for performance reasons), so a sleight-of-hand should work well. You could even have both instances always instantiated/loaded but simply manipulate .Visible of each one appropriately.