These preferences are used to help the audience viewing the graph to see the important comparisons.
For both Interaction Lines and X Axis Lines, the X Axis controls which treatments are displayed from left to right on the graph. The top corresponds to the left-most treatment and the bottom of the list is the right-most. If the level is highlighted blue, it will be shown. Hold the Ctrl key to select multiple treatments.
For Interaction Lines only, the Y Axis controls which treatment lines are displayed within the plot. The treatments top to bottom correspond to the treatments shown on the legend also in top to bottom order.
Show unselected X Axis labels: leaves a place holder space for the treatments that are not displayed. If turned off, they are removed from the plot entirely.
Click the Default button to put everything back on the graph.