Terry,
Thanks for spending the time trying to fix this. The control is now working inside the modalpopup/tabcontainer(thank you for that), BUT now stopped working on a regular page with a scrollbar(i.e. without the modalpopup or a tabcontainer). This was working fine before the fix.
To test this issue, just go back to the same code above and add another ajaxuploader right next to the Button1 (Like this):
<asp:Button ID="button1" runat="server" Text="Postback" />
<CuteWebUI:UploadAttachments runat="server" ID="Uploader2" MultipleFilesUpload="true" InsertText="Regular Upload"
UploadType="Flash">
<ValidateOption MaxSizeKB="10240" />
</CuteWebUI:UploadAttachments>
You can also see that the scroll bar is going crazy. If you try to scroll to the bottom of the page, the page just keeps growing...
Thanks a lot!!