There are two colors that we use to identify sketch-elements that are not-fully-defined and fully-defined.

The colors depend on the theme you are using.

Not-Fully-Defined

Typically Blue - sketch-elements that are not yet fully constrained.

You will notice that as you add sketch-elements to a Part they are Blue

This is the color of 'under-defined geometry'. You will find that you can still drag Blue sketch-elements.

CAD-Lines are a deep green.

Fully-Defined

Typically Black - fully defined or constrained sketch-elements.

Ideally, you should add dimension and constraints to your sketch so that all the sketch-elements are Black. This means the sketch is fully-defined.

There is no correct or incorrect way to define the sketch-elements.

Dimensions and Constraints should agree with the design intent.

Reference Geometry is Orange.

Grey when Show / Hide other Kinematic and Sketch-Elements tool is active, Part-Outlines, Axes, sketch-elements and Joints in the other Mechanisms are colored Grey.

When dimensions are used to control an element, they are Grey

For example:

•Dimension of a Line that is the Line-between-centers

•Dimension of an Arc for a Pulley

•Dimensions added to Design-Sets