Click the View | Show/Hide | Rulers command to toggle between showing and hiding the rulers on the top and left sides of the main plot window. When the Rulers command button is depressed, the rulers are shown. Surfer will remember your preference to have the ruler on or off when the program restarts.
You can also right-click on a ruler and click Ruler and Grid Settings to open the Options dialog Rulers and Grid page.
Rulers and Grid
View Tab Commands