Is there any way to optimize the implementation of the IWCheckListBox to allow it be efficient even with a large number of elements?  Even at 100 elements the system gets slow and above 500 it makes the browser VERY unresponsive?

Other than using a multi-select listbox is there a suggestion for a different way to allow a user to select multiple items from > 500 or 1000 elements?  I realize I could do some paging etc. and handle it on the server side but it seems there might be a way to still do this in Javascript efficiently.
I would suggest using multiple lists as the IWCheckListBox was not designed to be used with such a large number of elements.

This is a good suggestion however and we'll consider implementing this for a future version.