void reload() {
		Program p = program;
		program = null;
		listing = p.getListing();
		viewList.clear();
		createRootNode(p);
		setProgram(p);
	}
Notification made when the program was restored from an
undo operation.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/ProgramDnDTree.java