As the NamespaceIndex of the same Namespace of a NodeId can vary from AddressSpace to AddressSpace, while referring to the same namespace, representing NodeIds with the NamespaceUri should be preferred over NamespaceIndexes.
The settings dialog should be updated to read and insert the NamespaceUri of a namespace on drag-and-drop action to have an ExpandedNodeId string represetation like "nsu=<namespace-uri>;..." instead of "ns=<namespace-index>;...".
After all, the readSetting() method should be extended to convert ExpandedNodeIds back to the according NodeIds, as the current scripts expect to retrieve NodeId string representations, so the settings stay compatible using both ExpandedNodeIds and NodeIds.