Once you have created a dead key, Ukelele will automatically enter the dead key state so that you can create the appropriate output. You keep on editing output in that dead key state until you either enter a new dead key state, or leave the current one.

To leave a dead key state, either choose “Leave Dead Key State" from the Keyboard menu, or click the Leave button on the toolbar.

You can always return to editing a dead key state at a later time. Either choose “Edit Dead Key...” from the Keyboard menu, or click the Enter button on the toolbar. In the dialog that appears, choose the name of the dead key state and click OK. If the Inspector window is open, you will see the name of the dead key state appear at the top of the dead key state stack.