I know that the colours were recently overhauled in the finance window, but I would like to suggest at least one change.
On the left are Protanopia (red deficient) and Deuteranopia (green deficient). On the right is normal vision.
Note how the black text on red becomes completely illegible. The rest are, at least, legible.
It would be best if red and black are not used to contrast each other.
In gimp, a quick way to check how safe your colours are to go to "view -> display filter -> colour deficient vision".
(http://i199.photobucket.com/albums/aa131/AEObikes/simutrans/color_selection.jpg)