What about "het laken is in de kast"? Would you ask "Waar is het laken" or "Waar ligt het laken"? This may be nonsense, but maybe "ligt" in this case means that the sheet is placed in the closet; that is it's usual place, it spends time in there... rather than it is just currently in there.
Imagine a cartoon where objects are alive, and the sheet hid in the closet. The bed asks the pillow where is the sheet, and the pillow says "het is in de kast"
Does any of this make sense?
There are several mistakes in that link. Closets aren't necessarily small compared to wardrobes. In fact, a small bedroom can be referred to as a closet. The main difference is that a wardrobe is used specifically for clothes while closets are more general. A closet is usually a built-in side-room or recess, whereas a wardrobe tends to be a free-standing piece of furniture, although it can also be a room.
There seems to be a misunderstanding of seasonal wardrobes too. A summer wardrobe is the collection of clothes used in summer, rather than a piece of furniture that contains them. It's not unusual to keep your summer wardrobe and your winter wardrobe in the same piece of furniture, which is also called a wardrobe.
A wardrobe in the theatrical context is usually a room rather than a piece of furniture.
I know what you mean, but when we talk about wardrobes this is what comes to my mind: http://cdn.homedesignlover.com/wp-content/uploads/2013/05/15-oak-red-floral.jpg
It's sort of the kind of wardrobe I have :) If you can call that a wardrobe (now I'm not sure anymore :P )