This functionality is available in the  State Machine and Activity diagrams.

In the State and Activity diagrams you can split a path into two paths, by dropping a shape on it. This is valid for Transition/ Control Flow/ Object Flow relationships and allowed to connect with these path elements.

To insert a new shape by splitting path on the diagram pane


  1. Select the shape you want to insert or create a new one.
  2. Drag the shape on the path (the path is highlighted in blue) and drop it.
  3. In the Split Transition dialog click the appropriate button according to were do you want to insert the shape on the path:
     

 

In the Split Transition dialog, select the Remember my choice check box and the next time the shape will be inserted before or after the path, depending on your selection made this time.

Split Transition dialog