protected void addCancelButton() {
		cancelButton = new JButton("Cancel");
		cancelButton.setMnemonic('C');
		cancelButton.setName("Cancel");
		cancelButton.getAccessibleContext().setAccessibleName("Cancel");
		cancelButton.addActionListener(e -> cancelCallback());
		addButton(cancelButton);
	}
Adds a "Cancel" button to the button panel.  The protected method
CancelCallback() will be invoked whenever the "Cancel" button is pressed.
Ghidra/Framework/Docking/src/main/java/docking/DialogComponentProvider.java