Both viewer and layer have property called CustomData which allow to store user defined data on a list as:
MyProgam.Value1=this is my private data MyProgam.Value2=this is also my private data
Property is available as string list:
TGIS_Layer.CustomData.Values[ 'MyProgam.One' ] := 'Stored with layer' ; TGIS_Viewer.CustomData.Values[ 'MyProgam.One' ] := 'Stored with viewer' ;
CustomData are stored/retrieved automatically with project and configuration files. Purpose of this object is to provide DK developer ability to store custom setup like custom filters etc.