How Google desktop search is opening files in foreground?

Hi,
My application is webservice and the browser is the UI to the user.

I want to build similar experience as google desktop search is giving while opening the file. Suppose the user is searching for a particular file and he clicks on it in the browser, google desktop is opening it in foreground, i tried to do this in my app but it some times opens in background.

I used CreateProcess and then AllowSetForegroundWindow with the dwProcessId and then SetForegroundWindow on the top most window, but AllowSetForegroundWindow was failing sometime.

I think here the issue is my application is running in background and the foreground application is the browser.

Can anyone help me here? i want to give the same experience as google desktop while clicking the file.

Thanks in advance.