Pictures turn to grey box when scrolling / zoom etc

Hi,

One of our customers has an issue with DraftSight where they add a reference picture (e.g. JPEG of a floor plan) and it displays correctly but then if they zoom or move around the screen the picture changes to a grey box.

If they then change a parameter, say fade, by adding an extra 0 it re-appears.

They are using machines that have the Intel 4600 series graphics adapter with the latest drivers on Windows 8.1.

The software is a fresh install.

Any idea's as to what we could do would be gratefully received,

Regards,

Mark