Since version 3.1.0, it is possible to change some internal color
Copy the file NoniGPSPlot.ini from the directory where NoniGPSPlot is installed on your PDA, then edit it with a text editor.
You will find the following lines (you should have started at least one version 3.1.0 (or later)):
GPSMap|GPS_COLOR|Hex code|: Color of the cursor and info for GPS
GPSMap|GPS_COLOR_NT|Hex code|
GPSMap|SEL_COLOR|Hex code|: Color of the cursor and info in mode 'free movement'
GPSMap|SEL_COLOR_NT|Hex code|
GPSMap|NAV_COLOR|Hex code|: Color for navigation
GPSMap|NAV_COLOR_NT|Hex code|
GPSMap|DRAW_COLOR|Hex code|: Color main display
GPSMap|DRAW_COLOR_NT|Hex code|
GPSMap|BACK_COLOR|Hex code|: main background color
GPSMap|BACK_COLOR_NT|Hex code
_NT Versions are used in night mode.
The hex code are RRGGBB (eg 0000ff for blue, to green 00ff00, ff0000 for red etc. ...)
If you want to restore the default values, delete those lines.