blissful granite
The support beams for the display building does not extend into the bottom of a trash building if the display building placed placed on the 3rd floor, unlike a display building placed on the 2nd floor which correctly has it's support beams extend into the bottom of the trash building.
Note: in the image accidently shows a button on the second floor instead of a display, but I assure the the results are exactly the same regardless.
spice linden