Theorectically you could save whatever you want in there as long as you react to the App.SerializationManager.Serializing and App.SerializationManager.Deserializing events.
But basically DotSpatial uses it to save the layers from the legend with all the drawing information.
Layer data can be saved by calling FeatureSet.Save() so not sure what data remains that you'd want to save to the dspx.
But basically DotSpatial uses it to save the layers from the legend with all the drawing information.
Layer data can be saved by calling FeatureSet.Save() so not sure what data remains that you'd want to save to the dspx.