You can control the Color for the two states of Geometry.

•Geometry Under Defined - typically, near to Blue

•Geometry Fully Defined - typically, near to Green

See Application-Settings > Graphics tab > Display Colors

A dimension is Gray if it:

•has been added to a Design-Set

•is the length of the Line between the center of two gears in a Gear-Pair

•is the radius of a Pulley

•controls the length of a Motion-Path

Other Colors

•Reference Geometry is Orange