Rubber Stamp tool

Use this tool to replicate objects. When you first open OmniGraffle, the Rubber Stamp tool is empty, and the dot on its side is hollow. Select it and click any object on the canvas to grab the object into the stamp; the dot becomes filled. Once the stamp contains an object, each click on the canvas creates a new copy of the object.
To reset the contents of the stamp, select Clear Contents from the tool's pop-up menu; you can then grab a new object. You can also Option-click a different object to replace the stamp's contents.
This tool is hidden by default; you can use the Tool Palette preferences to put it in the tool palette.