@Override
				public void actionPerformed(ActionContext context) {
					Object contextObject = context.getContextObject();
					GTree gTree = (GTree) contextObject;
					TreePath[] paths = gTree.getSelectionPaths();
					for (TreePath treePath : paths) {
						GTreeNode node = (GTreeNode) treePath.getLastPathComponent();
						int recurseDepth = callTreeOptions.getRecurseDepth();
						gTree.runTask(new ExpandToDepthTask(gTree, node, recurseDepth));
					}
				}
A variable used to restrict open-ended operations, like expanding all nodes or filtering.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/calltree/CallTreeProvider.java