private void blockTwoStartChanged(Address start) {
		setStatusText("");
		boolean isValid = checkBlockTwoStartChanged(start);
		setOkEnabled(isValid);
	}
Listener on the RegisterField inputs; update other fields when either
of these fields change.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/memory/SplitBlockDialog.java