Curves
Tools > Options > View > Display Modes > [Mode Name] > Objects > Curves
Curve settings
Curve color usage
Specifies a color for all curves.
Use object's color
Uses object's display color.
Use single color for all curves
Specifies a color for all curves.
Curve color
Sets the curve color.
Curve width usage
Use object's width
Uses object's linetype settings.
Pixels
Width in pixels.
Scale
Scale factor of width.