I still have floor space but it won't allow me to drop down a basket of fruit, while 9 lose pieces of fruit are accepted without a problem. My other exhibit room is 100% filled with ores and they never had any problems. How do I know when it's full or what is causing it?
It's hard to tell when something is full. I don't know the complete amount, but a certain amount of furniture, that you can touch and push/pull, can be used, and then the room is full. The rest of the space can only be filled up by the items (fortunes, single pieces of fruit, etc.) that you drop on the ground and can walk over.