I too needed to change the colours of my MFDs since I found it difficult to differentiate between them in certain instances. I played around with the Default.cfg file quite a bit to find out which colour did what, and came up with what I think is a reasonable list of the elements. I have included it below. Basically I set every colour to White and then, one by one, set a colour to Blue and tried every MFD to see what showed up as Blue. Hope this might help.
The file ...\Orbiter\Config\MFD\Default.cfg (or wherever you have installed it) contains the main defaults for the standard Orbiter MFD colours. Here is mine as it is now:
; The colour values must be in upper case hexadecimal, in the sequence BB GG RR (blue green red - but without the spaces)
; So blue is FF0000, green is 00FF00 and red is 0000FF
; White is FFFFFF
; Note that TransX, Radio and Aerobrake mfds are not affected, so they must use inbuilt colours
COL_0_BRT = 00EE00 ; green
; orbit mfd my orbit & data
; surface mfd values
; map mfd my orbit & data
; hsi mfd values
; vor mfd values
; docking mfd values
; align planes mfd values
; sync orbit mfd text
; transfer mfd text
; com/nav mfd all values except highlighted one
COL_0_DIM = 00EE00 ; green
; map mfd horizon circle
; sync orbit mfd my orbit & radial
; transfer mfd my orbit, radials & hto
COL_1_BRT = FF3333 ; blue
; orbit mfd target orbit & data
; docking mfd some text (speed)
; align planes mfd 'AN' 'DN' 'P' text & node line
; transfer mfd target text
; com/nav mfd highlighted text
COL_1_DIM = FF3333 ; blue
; sync orbit mfd target orbit & radial
; transfer mfd target orbit & radials
COL_2_BRT = C0C0C0 ; light grey
; orbit mfd projection types text
; surface mfd ladder lines & pitch dots etc
; map mfd menu text & base markers
; hsi mfd compass generally
; docking mfd some text (angles)
; com/nav mfd XPDR Transmitter text
COL_2_DIM = 9C9C9C ; grey
; orbit mfd Frm & Prj titles, and planet surface
; docking mfd bullseye graphic
; align planes mfd Ref & Tgt titles
; transfer mfd Ref: title and value, intersection line
COL_3_BRT = F55FFF ; light purple
; (doesn't seem to be used at all)
COL_3_DIM = AC42B3 ; medium purple
; (doesn't seem to be used at all)
COL_4_BRT = 003937 ; dark brown
; map mfd coastlines
COL_4_DIM = 732D77 ; dark purple
; (doesn't seem to be used at all)
The file ...\Orbiter\Config\MFD\Default.cfg (or wherever you have installed it) contains the main defaults for the standard Orbiter MFD colours. Here is mine as it is now:
; The colour values must be in upper case hexadecimal, in the sequence BB GG RR (blue green red - but without the spaces)
; So blue is FF0000, green is 00FF00 and red is 0000FF
; White is FFFFFF
; Note that TransX, Radio and Aerobrake mfds are not affected, so they must use inbuilt colours
COL_0_BRT = 00EE00 ; green
; orbit mfd my orbit & data
; surface mfd values
; map mfd my orbit & data
; hsi mfd values
; vor mfd values
; docking mfd values
; align planes mfd values
; sync orbit mfd text
; transfer mfd text
; com/nav mfd all values except highlighted one
COL_0_DIM = 00EE00 ; green
; map mfd horizon circle
; sync orbit mfd my orbit & radial
; transfer mfd my orbit, radials & hto
COL_1_BRT = FF3333 ; blue
; orbit mfd target orbit & data
; docking mfd some text (speed)
; align planes mfd 'AN' 'DN' 'P' text & node line
; transfer mfd target text
; com/nav mfd highlighted text
COL_1_DIM = FF3333 ; blue
; sync orbit mfd target orbit & radial
; transfer mfd target orbit & radials
COL_2_BRT = C0C0C0 ; light grey
; orbit mfd projection types text
; surface mfd ladder lines & pitch dots etc
; map mfd menu text & base markers
; hsi mfd compass generally
; docking mfd some text (angles)
; com/nav mfd XPDR Transmitter text
COL_2_DIM = 9C9C9C ; grey
; orbit mfd Frm & Prj titles, and planet surface
; docking mfd bullseye graphic
; align planes mfd Ref & Tgt titles
; transfer mfd Ref: title and value, intersection line
COL_3_BRT = F55FFF ; light purple
; (doesn't seem to be used at all)
COL_3_DIM = AC42B3 ; medium purple
; (doesn't seem to be used at all)
COL_4_BRT = 003937 ; dark brown
; map mfd coastlines
COL_4_DIM = 732D77 ; dark purple
; (doesn't seem to be used at all)