private JPanel createLegendPanel() {
		JPanel legendPanel = new JPanel(new BorderLayout());
		legendPanel.add(new BitFieldPlacementComponent.BitFieldLegend(null), BorderLayout.WEST);
		return legendPanel;
	}
<code>BitFieldEditorPanel</code> provides the ability to add or modify bitfields
within non-packed structures.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/compositeeditor/BitFieldEditorPanel.java