The palette shows a status of elements selected in the model (zones and objects) in terms of their relation with rooms and items planned in dRofus. It also provides an interface for changing that status (linking and unlinking zones and objects) and a navigation tool (Open Room Data).
It does not appear automatically the first time you run ArchiCAD. You need to explicitly open it through the dRofus menu:
The dRofus Property Panel will then show up with the option to Login as follows:
