Items in the room can either be visually checked in the Items in room window or in the Item occurrence window, or you can get an exception report of the desired room. The last option is the best to check a large number of rooms.
Validate occurrences between dRofus and model
Occurrences in room can be validated between dRofus and the model by selecting the Occurrence match panel on the right side list of available panels.
This will add the Occurrence match panel to the interface. In this list you can see two columns: (Quantity) In the database and (Quantity) In the model. If the quantities match the row will be highlighted in green. If the quantity do not match, the row will be highlighted in red. If you want to validate several rooms you can multiple select more rooms in the Room panel, and the list in Occurrences match will automatically update.