Keypads are a control that allow for simple user entry of a passcode which can initiate a set of actions, or display a specified popup window. For more information regarding passcodes, see Keypad Passcodes.
In addition to the Basic Properties, a keypad widget has the a "Show Cancel" property.
With a keypad selected, change the "Show Cancel" property to "Yes". ControlDesigner draws a "Cancel" button on the right side of the "Enter" button on the keypad and adds a Cancel action to the "Action Editor".
See Add or Edit Keypad Actions for details.