KOTS

When dropping an item on container, item the game logic should attempt to put the item inside the backpack. If that fails, no action is performed.
Dropping an item on main backpack icon (directly on backpack slot) shows "you cannot dress this object here" error. It should try to put item inside the backpack instead.
Dropping an item on other stored container icon just attempts to put that dropped item in same container as that stored container.