I guess this is a little off topic, but it is a bug in FRED.
Anyways, I have FRED_OPEN 3.6.5, and in this all the z-axis markers (the little green or white lines) are shown as if viewing from Alpha 1, even though the actually camera viewing at a different angle and from a diff location. When you move the camera around, the z-axis markers stay the same.
Also, I have noticed that the background editor is not working very well. I am not sure that it actually positions the background images where you specify them to be, as every image i have added it always at 0,0,0.
Not, a SEXP bug, but a bug nonetheless.
Thanks