Current/Selected Instance
The shipped sample command handler DF_DET14 shows you the current and the selected instances in any instance list.
In the following example DF_DET14 has been assigned as the command handler for the Status command. It shows the current instance and all the selected instances in an Employee instance list:
Note the dotted lines around Paul Smithson indicating it is the current instance.
Try assigning DF_DET14 as the command handler for a business object to see how GetCurrentInstance and GetSelectedInstance works. Remember that the command you assign it to has to be an Instance Command.