abds,
Thanks for the reply. I don't believe it's an OnPostBack problem. I have 3 frames that I am working with. I have a tree, param, result frames. In the param, the user types in the search parameters, presses the search button in the param frame, it grabs data from the tree and then displays the results in result frame. My problem is that there is no consistent order in which the frames load, which will result in errors if it doesn't happen correctly. I originally had the tree selections passed in the querystring, which works great unless the user selects a lot of items in the tree, then the querystring exceeds the length limit. There are thousands of items in the tree frame, so if the user checks the Root, then the entire tree is selected, or a couple of the parent nodes of the tree, which also exceeds the querystring length limit. Thanks in advance.