We are having a hard time figuring out a solution to a long running issue. We are using a RadListBox to display a list of items such as names on a page. There are 2 lists where 1 is the selector list and the second is the "selected" list. When the selector list gets to contain somewhere in the range of 2,500+ names, the transfer runs unacceptably slow. We've tried to disable viewstate, but that breaks our code since we need to handle the transfer on the server side via an AJAX call. When we debug the code, it takes almost 25 seconds for the server-side CodeBehind method to execute.
Please advise on what can be done to improve performance for a RadListBox with transfer enabled that contains large lists of data.