You can show or hide the rulers in the Unified Modeling
Language (UML) diagram editor.
You must have a diagram open and active in the
diagram editor.
To show or hide the rulers, right-click an empty space
in a diagram; then click .
Note: When you turn on the rulers, the guidelines
turn on simultaneously. You can drag the vertical and horizontal guidelines,
which are anchored at the upper-left corner of the diagram editor,
onto diagrams and then line up diagram elements to the guidelines.