Alright - this seems like a great idea - thanks for sharing in public forums - this will certainly help other people, since this seems like a common scenario (closing window from child page and then executing postback logic).

I will try to have this covered in samples/help or DevCenter as well. 

Rumen I found a work around.  I use 2 buttons on the form.  One for "Send" and one to "Close"

The Close button uses the Clientside script.  However, when the message is successfully sent I give them a webdialog confirmation in the webdialogwindow which clears the email form and essentially resets the form!

This will probably not work since the first page will never be reached when you click "Send" - it will go to second page and return there. The only solution I see is to register javascript from server using

Page.ClientScript.RegisterStartupScript and execute javascript that will close the window (using the javascript code I sent you before). I think this will work.

The other possible idea is to first close the window with javascript (using again the same code) and then do the "Send" postback - this can be done using the "click()" button idea I send you (or you can use LinkButton and handle OnClientClick) 

Rumen, once I click the button and the email is sent I want to close the window.  Is there no way cast the page.previous or page.parent and get the webdialogwindow and run webdialogwindow1.windowstate=hidden?

So, just to make sure I understand, you want to first close the window, then execute postback?

calling _doPostBack is possible, if you can emulate the EVENTTARGET and EVENTARGUMENTS the framework is generating for the button. Or you can call the click() function of the button, e.g.

<asp:button runat="server" ID="Button1" OnClick="ServerSideFunction" />

<script type="text/javascript">

var button = document.getElementById("<%= Button1.ClientID %>"); 

button.click() 

</script>