Watin AttachTo popup window - testing

Question

We are using Watin to automate the website testing and try to implement the following: Click on a button to bring up popup, click on the Generate button on the popup window to generate file. We wasnt able to get the popup window using watin. ERROR: "Could not find an IE window matching constraint: Attribute 'href' matches 'Regenerate'. Search expired after '30' seconds." Please give a hint on what has gone wrong. Your help would be much appreciated.
The code snippet as below:
ieInstance.Button(Find.ByName(Button1)).Click();
ieInstance.WaitForComplete();
var popupUrl = new Regex("Regenerate");
//part of popup URL: "RegenerateDialog.aspx?Type="
var popupBrowser = Browser.AttachTo<IE>(Find.ByUrl(popupUrl));
if (popupBrowser != null)
popupBrowser.Button(Find.ById("RegenerateDialogBtn")).Click();
The popup window code as below:
function ShowEXPFileWindow(Type)
{
//do some stuff
var oWnd = window.radopen("RegenerateDialog.aspx?Type=" + Type, "RegenerateDialog");
oWnd.set_title("");
oWnd.center();
}
HTML to bring up popup window:
<td><input type="submit" name="ctl00$Body$ConfigRadGrid" value="Regenerate" onclick="ShowEXPFileWindow('OD'); return false;" class="submit" /></td>

Answer 1

Instead of
ieInstance.Button(Find.ByName(Button1)).Click(), use
ieInstance.Button(Find.ByName(Button1)).ClickNoWait()
and check. Is it possible to post the image of the pop-up window? or when you click on button, which control is selected by default? If it is 'Regenerate' then try to press 'Enter' Key and check.
Is the pop window is another IE window? If yes, then attach it using
Find.ByUrl(url => url.Contains(expectedURL))