void expand(ProgramTreeActionContext context) {
		ProgramDnDTree tree = context.getTree();
		tree.expandNode(context.getSingleSelectedNode());
		plugin.contextChanged();
	}
Delete node(s) from the tree; called from the action listener
on the menu.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/programtree/ProgramTreeActionManager.java