Lenovo P50 laptop, 2 mo old, NvidiaM1000M, driver updated, Windows 10, two Dell ST 2421L monitors. When I move the Firefox browser window from the monitor to the other monitor, or from laptop screen to either monitor, the firefox screen goes blank. When it opens on either monitor, it works fine. Problem only occurs when dragging the window to either of the Dell Monitors. Dell does not have Windows 10 drivers for ST 2421L monitors.Moving blanked window to laptop monitor restores view (black screen goes away) but blanks if moved back to Dell monitor, Help appreciated.