Hi,
I'm not sure what you mean by the "highlight" area, but it looks as if you can use (in PE6) :
File > Options > Colours / Fonts : Then the Edit button gives simple control of the main colours, or the Manual Edit appears to give control of more colours where the .....Color("#RRGGBB") field selects the intensity of the Red, Green and Blue Bytes.
Cheers, Alan.
Same issue here, I can't find a highlight setting. Would have been nice to have a dark mode because it so much easier on the eyes. Took a while fiddling with colours and they probably don't look "standard" now.