Problem in modal pop in asp.net 2008 ajax

[hozsam]

Hi, I m using ajax modal pop up extender control in my ASP.Net 2008 website. On click of some option button it opens up the modal pop disabling the base page. Although it disables the page ... mouse clicks does not work but tab key do work on the base page if there are option buttons on the page. Can anyone give a suggestion or solution to disable the option buttons on base page through tab keys? Or if there is any other solution for opening pop up windows in asp.net website? I also want to open another modal pop up from a modal pop up itself. Is it possible ? caz when i use it, it behaves weirdly i.e. does not work properly. Thanks,