I've been having a problem with items left in doorways that leave the doorways open.
Sometimes it's because there is no stockpile that can accept the item. Other times, I've had that problem because a new worker wanted to use a workbench and the old item needed to be removed -- and it was removed to a place that kept a door open.
I think a doorway should be the last place (last, not completely unacceptable) that an item should go. It really plays hell with air temperatures and safety concerns.
The mechanics there don't quite make sense. There are other (non-stockpile) squares available to drop things, yet the spot chosen conflicts with the door, thus the temperature and the defense.
Worse, it's an unfinished cloth touque preventing the door from closing and thus compromising the entire colony. :(