The thread you referenced talked about the "Current Selections" object, i.e the global tracking object of selection state.
Is that what you are after? Or do you just which to grab the selections in a particular field?
If you wish to fetch the data for a particular field in the data model you can use the Field interface qlik.app.field (Field API)
You can also use the GetObject method if you wish to fetch a specific object model and then inspect that.
Just not that a Filter Pane is just a concatenation (a GenericObject) of multiple Fields (GenericObjects with a ListDef as a child of the Filter Pane) so the selection states will not be on the Filter Pane but on the individual Fields.