If you’ve ever tried running multiple browser windows at the same time—whether for traffic generation, ad engagement, or behavioral simulation—you’ve probably noticed something strange:
No matter how many windows you open, only one of them is ever “active.”
This isn’t a bug.
It’s simply how browsers work.
In a normal desktop environment, the operating system grants focus to only one window at a time. That one window becomes the active tab. Every other window—even if fully visible—is technically inactive.
This behavior is easy to observe using a simple visibility/focus detector like: