Video "corruption" when using second monitor with laptop

My Gateway ec1433u laptop has a VGA port on the side, and when at home I typically plug another monitor into it for extra screen space. I can’t get it to work with x86_64 11.3 GNOME however. What’s odd though is that it works fine with gdm (second photo).

Here’s a photo.
Second photo.

This is probably useful: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)

Any thoughts? Cheers.