May have located a bug. Interesting really, if I replace PopUpItem image with my modified file, only modifications made to it were adding edges, colors are the same. The file displays a gray hue. If I replace the file with resource tuner it displays as it should, but messes up the alignment and corrupts the image, displaying the "white" background. If I replace that same file with the original file from Aero 980 it displays fine, same colors, no modifications.
Original 980 (Menu_PopUpItemImage)
replaced file with WSB, displays as:
Modified (Menu_PopUpItemImage)
replaced file with resource tuner, displays as:
replaced file with WSB, displays as: