Furniture is filtered out automatically from the Grid and Viewer. Furniture is still published, but it is not downloaded until the furniture filter is deleted.
As furniture is not downloaded until the furniture filter is deleted, you will not see furniture in ghosted mode as you see Detail Items, Rooms, and Spaces, which are also automatically filtered out of the Viewer and Grid.
There are several reasons for this. First, furniture geometry is often both highly complex and abundant. This potent combination can generate significant performance problems for the viewer. It's not uncommon for the viewer to run out of memory where furniture geometry is displayed. This happens for about 10% of models. We display "ghosted" geometry for things that are filtered out, so simply not including it in a filter isn't sufficient to prevent this problem.
However, to make your furniture visible, simply click on Visibility Settings, and then click the drop-down for ignored categories. De-select the Furniture check box and Update the Visibility Settings. Finally, modify or delete the new rule created, and Update once more.