I have recently purchased a XPS M1530 laptop with a E248WFP 24 inch monitor which I have connected to the laptop.  I have noticed that on darker background pages that there is a flicker or shimmer in the screen on the monitor.  This flicker is not evident on the laptop screen.  I have tried changing the screen resolution to the highest setting and the refresh rate to the highest setting but it hasn't improved it.  The flicker scrolls down from the top of the screen to the bottom.  Any help would be appreciated or have I just got a bad monitor

Regards Rod.