My setup is sensitive to any noise so my solution was simply to eliminate the wireless interference makers including Xbox controller, network and keyboard. I also completely reworked the grounding of eveything in the setup.

My control box with a CNC4PC BOB and 4 Gecko Drives is aluminum and hangs on the wall behind and off to the side of the mill. I have a clear plastic cover on the box so that I can observe the many indicator lights on the devices inside. I suspect the polycarbonate plastic is useless as shielding.

Is there any way to shield while still being able to see the internals? I was thinking a metal screen like aluminum window screening might provide some shielding and I could probably see thru that well enought to see the fault indicators, etc.

Another though I had was the sunscreen film for windows. I recall reading that this material is a metal coating on mylar or something like that. If that is a metallic coating, then perhaps that would provide shielding.

Any thoughts on this?

I would try the metallic screen material, it would basically be the same as a Faraday cage. It won't let through any RF with a wavelength greater then the mesh hole size. You just need to get a good electrical 'seal' around the lids perhiphery.