Fiddler shows which sessions were loaded from a SAZ file by changing their background color. When the list window uses default colors, the effect is very subtle. As you've seen, it's much different when the Windows theme is "dark."
It's easy to fix.
In the QuickExec box below Fiddler's web sessions list, type
prefs set fiddler.ui.Colors.LoadedFromSAZ DarkSeaGreen
and hit Enter.
You can use any color name from http://www.opinionatedgeek.com/DotNet/Tools/Colors/
or one of the HTML color strings (e.g. #1C1C1C )
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