Enable concurrent test execution

I am trying to test the popup caused by a copy operation. My application hooks into the copy call and waits for user response on the popup(which has its timeout). Only after a pop-up response does it release the copy call. Now this causes a problem because my script gets stuck on the copy statement and doesn't pass control to the pop up handling statement until the pop up times out. Is there any way i can handle the pop up in this case?