@Override
		protected void expandNode(GTreeNode node, boolean force, TaskMonitor monitor)
				throws CancelledException {
			TreePath treePath = node.getTreePath();
			Object[] path = treePath.getPath();
			if (path.length > maxDepth) {
				return;
			}

			if (!force && !node.isAutoExpandPermitted()) {
				return;
			}

			CallNode callNode = (CallNode) node;
			if (callNode.functionIsInPath()) {
				return; // this path hit a function that is already in the path
			}

			super.expandNode(node, false, monitor);
		}
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