Ok, this is probably got to be one of the coolest things that they have added that in not really talked about. The form tag now supports a property called DefaultButton. This property allows you to specify which button is clicked when the enter button is pressed. Even cooler is that you can also specify this property on a panel. Why this is cool is that on the home page we can have the LocationTime control submit to GetRates when the enter button is pressed. At the same time, we could also have another textbox that submits to location search whenever the enter button is pressed.
Here is an example:
<Form id="Form1" runat="server" DefaultButton="GetRatesButton">
</Form>
Read the complete post at http://www.dotnettipoftheday.com/blog.aspx?id=190