BlockUI works strangely from Visual Studio ?

BlockUI works strangely from Visual Studio ?

Using the BlockUI plugin I find strange behaviour from within an ASP.Net page.

I've implemented one of the BlockUI plugin demos (http://malsup.com/jquery/block/#dialog) within an ASP.Net page.

When I serve this page from Visual Studio (MVWD 2010 Express) the 'Would you like to continue' dialog appears as it should but then (rather than waiting for me to press a button) just disappears after 1 to 2 seconds.

Can anyone explain why this might be ? The HTML rendered by the ASP.Net is attached to this post (I had to suffix it .TXT to allow it to be uploaded).

Would appreciate any suggestions.