Fluid is Stuck at 940

Responsive is nice when sites are viewed on smaller devices, but should also be able to expand to larger resolutions. Especially true with retina tablets and pcs connected to HDMI 52 inch flat screens.

When i select the fluid option I would expect the body content and left, right or left/right columns to expand just as the header background and site background does.

Is their a css fix for this?
Should fluid do this but there is an issue with the current theme?

Thanks for any help.
Mike