After finding the awesome fix provided by RegentEagle for the room marker and havok issue (http://www.gamesas.com/index.php?/topic/1148040-how-to-fix-lighting-havok-and-rendering-issues), I found that lighting was still a bit dogy. Some cells seemed to update lighting straight away, whilst others broke when you moved a light source and required a refresh of the cell view. I've took a look at this, and have found that if you add a room marker to the cell, any size, anywhere, then lighting works properly in the geck. It's weird but it's kind of a solution

It doesn't work that way for me. Even in cells with roommarkers & portals lighting update needs a refresh.

Have you applied the other fix here?

http://www.gamesas.com/index.php?/topic/1148040-how-to-fix-lighting-havok-and-rendering-issues

Great fix!
Thanks, with these fixes the GECK works like its supposed to now.

I place one and lighting still doesnt show up.