A drop-down box allows you to specify the radius of the solid circle that is placed at each data point on the plot. If "Auto" is selected, then the program chooses a radius according to the number of points in the plot. If "Line Only" is selected, then no circles are ever drawn. Otherwise, the user can select any radius from 1.0 to 5.0 pixels in steps of 0.5 pixel.
Click the Apply button to implement the change.
This option is non-volatile, in that it is saved with other preferences and restored the next time the program is restartd by the same user.