Unfortunately I never found a way of changing the foreground colour within the screen editor or with any external wxform builders, i may be wrong but I came to the conclusion that wxlua/wxwidgets was using the system colours for sliders and other controls so it could use the windows themes.
Again the leds are a very hit n miss thing - every now and then even during normal running the background of these can turn white, unfortunately this is not a mach4 coding error, it is somewhere between wxwidgets or wxlua Z height control.
DazTheGas