DataDomain intention is to provide a namespace for entities.
Still there is one issue where namespace abstraction breaks - if two domains in the same project have DataMaps (or JDBC DataNodes for that matter) that coincidentally have the same name, there is a conflict in saving these maps, as such maps are stored in the same directory under the same filename.
A solution for the future release is to prepend DataDomain name to the map name (e.g. MyDomain.MyMap.map.xml).
Current solution maybe to generate the default map name not just as "UntitledDataMap", but "MyDomain.UntitledDataMap", and then also do the validation on save for any name conflicts. At least this will make users aware of the problem.