@Override
	public Icon getIcon(boolean expanded) {
		return TaintSliceTreeProvider.TAINT_ICON;
	}
For this plugin there are two trees side by side.
This tree is on the left.  This node is the "root" or at the top of the tree.  All nodes that flow from it
are actually HIGHER up in the call stack to get to this node. They are nodes that CALL INTO this node via
some call path.
Ghidra/Features/DecompilerDependent/src/main/java/ghidra/app/plugin/core/decompiler/taint/slicetree/InSliceRootNode.java