Click event fires twice with shortcut and focus

If you define a button and add a shortcut to it (enter key to submit button in a form) click event fires twice if focus is on that button.
Is this by design?
How can I prevent this?

Button button = new Button("Click me", 
						   e -> Notification.show(bean.getMessage(),
                                                  5000,
                                                  Notification.Position.BOTTOM_END));
button.addClickShortcut(Key.ENTER);

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