Lat/long graticule, secondary datum. You can only see this if the
pixel spacing on the map is less than the datum shift.

UTM grid, primary datum This will not appear until the map is
sufficiently large scale.

UTM grid, secondary datum. You can only see this if the pixel spacing
on the map is less than the datum shift. The shift in UTM is different
than in geographic coordinates.

The projection's native grid, helpful for systems like SPCS or the conic
projections.

You can set the color and line width for each to try to differentiate.
However, these are designed to allow you to display the correct, single grid,
and for educational purposes to see the relationships of the different grids.

Window allows you to modify parameters of the grid on
the map. You can:

Select UTM grid, lat/long graticule, both, or
neither.

Pick the maximum screen pixel size for the UTM grid, in meters. If
you want something at much smaller scales, use
Map projection zone
options.

Determine if the primary datum grid will be shown.

Determine whether or not the secondary datum grid will be
plotted. The datum for the main grids is selected in the Options
form (Datum tab). The secondary datum only can be changed on
this form. To change the primary datum you must close the
map window, select the new primary datum in the Options
from (Datum tab) and then reopen the map window.