I don't know what else to search for, but I'm just not seeing the answer - if it exists. I'm trying to do work in default game cells, at the moment the Museum of Technology - I find it really frustrating to try and pick an object in the render window without picking a light source (light source is in the way) - any way to disable lights as a pick-choice?
Yes.
Select, "View" and then "Show/Hide Window".
Check/UnCheck boxes in that Show/Hide Window to control what you see.
For single objects, you can hide them by selecting the object and typing "1" and "1".
Miax