The Diagram Symbols toolbar contains a Select button and a Text button. Use the Text button to add a text box to your activity diagram, as described in Using the text box feature. Use the Select button to cancel an operation, as described in Cancelling an operation.
You can insert a text box in an activity diagram and place text in the box, or edit existing text. To add text to an activity diagram:
A text box appears with the word "Text" within the box.
You can select and drag the text box to position it at a different point within the diagram.
If you change your mind about inserting a particular symbol in an activity diagram, you can cancel the insertion. To cancel an operation after you have clicked its button in the Diagram Symbols toolbar, click the Select button in the Symbols toolbar.
To cancel a transition link, use the Esc key. Each press of the Esc key undoes the last segment of the transition link.