private void collapseAll(GTree archiveGTree) {
		GTreeNode rootNode = archiveGTree.getViewRoot();
		List<GTreeNode> children = rootNode.getChildren();
		for (GTreeNode childNode : children) {
			archiveGTree.collapseAll(childNode);
		}
	}
Only shows up if all selected nodes are collapsable.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/datamgr/actions/CollapseAllArchivesAction.java