This dialog allows you to change the properties of the selected Line object. 

Line is used on

Mark one or more elements from the list of courses. When you mark "All courses", the Line object will be shown on all courses, including those courses that are not marked in the list

Mark one or more elements from the list of canvases. When you mark "All canvases", the Line object will be shown on all canvases, including those canvases that are not marked in the list.

Line Width

This is the width of the line in millimeters.

Line is dashed

Check this box to have a dashed line

Dash Length

Enter the length of each dash in mm

Gap Length

Enter the length of each gap in mm

Line Color

The color of the line can be controlled by the setting for the course overprint color.  This is the standard setting.  This is controlled by the checkbox "Use same color as course overprint".

If you want the line color to deviate from the course overprint color, uncheck the checkbox, and use the color button to choose a different color.