[Attack] Cross Site Double Clicking [Responsibility of] Nobody [Prevention] Not considered important [Future Standards] None [Example] 
Site A opens a popup for site B, then another popup for site A. Site A tricks the user to double click on the topmost page. The first click closes the topmost page, the second click performs an action on site B. A short while thereafter, site A can close the other popup, and the user might only notice a flicker.