private Component buildSpacerPanel() {
		JPanel panel = new JPanel();

		panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));
		panel.add(Box.createVerticalStrut(20));

		return panel;
	}
Method must be invoked following construction to fetch function info 
and update components.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/function/AbstractEditFunctionSignatureDialog.java