Here's an odd one; can you figure it out?

I'm setting my ASP.NET form action at design time, like so:

<form id="frmSubmit" action="paypal.aspx" method="post" runat="server">

but when I run it, the HTML source reveals that it's been changed without my permission, to post back to itself:

<form name="frmSubmit" method="post" action="default.aspx" id="frmSubmit">

Even the 'method' and 'action' attributes have been mysteriously switched.

Surely my VS.NET can't have a mind of its own?