Reference lines are vertical or horizontal lines in a graph, corresponding with user-defined values on the x-axis and y-axis respectively.
Each graph can contain up to 16 vertical and horizontal reference lines.
Add reference line
Right click in the graph and select "Add" and "Horizontal reference line" or "Vertical reference line".
Click in the margin of the graph to create a reference line and drag it into the graph plot area.
While you are dragging the reference line in the plot area, the corresponding value is displayed next to the reference line.
Format reference line
Right-click on the reference line and select "Format reference line" in the pop-up menu.
In the dialog box you can select line color, style and width, and enter an exact value for the reference line.
Note: all reference lines in one graph have the same color style and width.
Remove reference line
Right-click on the reference line and select "Remove reference line" in the pop-up menu.
Drag the reference line into the graph's margins.