Salem

You can light fireplaces without putting branches on there first.

I can verify this as well.

Also, when you right click on the fireplace, it looks like you have to option to drag branches to the boxes, but you cant. The only way to add the branches is to grab a branch and right click on the fireplace directly.

The fueling part isn't a bug, just unintuitive. It would be nice to be able to drop branches into the object window in addition to the right click method, though. The box is to add certain foods to when it has burned down to ashes.