Hi Mark - currently the way it works is when you set the X and Y axis colors under Options > Grid, that is not actually referring to the world X and Y axis directions, it is referring to the local horizontal and vertical axis directions of each individual grid.

So for instance the Front grid has a horizontal line and a vertical line. When you set the Y axis color under Options > Grid, it will set the color of the vertical grid line in every viewport, no matter what direction that grid line happens to be in a world direction.

That's kind of a remnant of an older concept of "every viewport has its own 2D coordinate system with its own grid".

I've been thinking of changing this to make it work more in the way you were originally expecting where it is focused on world axis directions instead. But that won't happen for v2, more likely for v3.

You can however set the colors for the little axis icon that you can optionally turn on in the lower left corner of the viewport (under Options > View > Show axis icon). The colors for those are settable in moi.ini, under:

[View]
AxisIconXColor=160,160,160
AxisIconYColor=160,160,160
AxisIconZColor=160,160,160

To edit moi.ini in v2 there is a button located under Options > General.

- Michael