Sometimes when working with your models, you might have done something you did not really intend to do. If this happens, the possibility to undo what you did can be very valuable. Poseidon for UML offers such an undo mechanism. The Undo function is not limited to the last change you made — you can undo all the steps you took prior to that, and you can even redo the things you just undid.
To Undo or Redo actions:
Main Menu — Select Undo or Redo from the Edit menu
Main Toolbar — Click
the Undo or
Redo button on the main toolbar
Quick-Keys — Use the quick-key CTRL-Z for undo or CTRL-W for redo