Choose View > Ruler Bars to toggle between viewing and hiding the ruler bars. When a check mark appears next to the Ruler Bars menu item, the ruler bars are displayed in the Form Editor.
Ruler bars run vertically, along the left side and horizontally, below the main menu bar at the top of the Form Editor.
Dimensions may be displayed in either inches or centimeters, by right-clicking on the Ruler Bar and choosing the desired measurement units from the popup menu.