@Override
	public boolean remove(DataType existingViewDt) {

		if (existingViewDt.getDataTypeManager() != this) {
			throw new IllegalArgumentException("datatype is not from this manager");
		}

		if (existingViewDt instanceof DatabaseObject) {
			dataTypeIDMap.remove(getID(existingViewDt));
		}

		return super.remove(existingViewDt);
	}
Get the {@link DataTypeManager} associated with the original composite datatype being edited.
@return original datatype manager
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/compositeeditor/CompositeViewerDataTypeManager.java