Black Screen on all Monitors

Hi Everyone, I'm hoping someone can shed some light for me. I have 3 monitors (1 is the laptop's built-in display, and the other 2 are connected to a Lenovo USB docking station). When I connect to this laptop either through my mobile or another laptop, only the laptop display is blacked out and the other two monitors are still visible. Is this a bug or limitation? Does anyone else have this problem?