@Override
		public BigInteger getIndexAfter(BigInteger index) {
			int i = index.intValue() + 1;
			if (i >= layouts.length) {
				return null;
			}
			return BigInteger.valueOf(i);
		}
Simple layoutModel to be used for the preview panel.
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/options/OptionsGui.java