When writing a .gephi file, Id attribute is not serialized to xml if it is the same as the node/edge int id to save space. But when reading the .gephi file, the int id is not set as Id attribute and adding the node/edge to dictionary does nothing.

This caused problems to add a column from an external csv file with Import Spreadsheet feature.
See forum thread http:// forum.gephi. org/viewtopic. php?f=29& t=1217