Opening new browsers window blocked inside GWT application

In my gwt, when a c开发者_如何学GolickEvent is fired, i create a webapp using rpc that i deploy on server and i return the url which i used to open a new window...I have to do some process before opening new window , I know it's because of that that browsers block the page but I do not know how to make it functional.

 url= someProcess();
 Window.open(url, "Test ", "");

is there any tricks to make the popup not blocked? Thanks in advance for your helps

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use a modal window rather than a popup i.e. a div overlay with the information that would have been in the popup - the browser would not be able to block this.