private void clearTrees() {
		if (inTree.getModelRoot() instanceof EmptyRootNode) {
			// already empty
			return;
		}

		updateTitle();
		inTree.setRootNode(new EmptyRootNode());
		outTree.setRootNode(new EmptyRootNode());
	}
A variable used to restrict open-ended operations, like expanding all nodes or filtering.
Ghidra/Features/DecompilerDependent/src/main/java/ghidra/app/plugin/core/decompiler/taint/TaintSliceTreeProvider.java