That sounds like what they are supposed to do to me. If you have a square and want a shadowy outline around it on the outside you can use an outer glow. If you want it on the inside you use an inner glow. You might try applying the effect to either layer to see if you get what you want. Drop shadows create a more precise shadow that can be moved away from the object you are shadowing. I would use it more to place shadows from an object up high or a more complex shape, like say if you were looking at an airplane from above, but wanted to place its shadow some distance away on the ground to show the direction of the light. Drop shadows show light directionality and shape where as a glow will just create a general fuzzy outline around what you are shading. The picture you posted looks like what should happen when applying an inner glow on the floor layer or an outer glow on the wall layer.