The way it was designed to work is when a selection is made all dependent selections get updated with the new selection options.
if you look at this example on the demo store, you will see that color is dependent on size. Not all colors are available for all sizes. So when selecting a size the ‘Color’ select gets updated with the available colors for that size.
I would think that a customer will be more frustrated with ‘guessing’ what options are available and making selections only to find out that this selection is not available.
After some research, and from our experience, we got to a conclusion that this default behaviour will be a solution that will have the most value for the different stores. This ,for now, can be changed by writing some custom code, but not through a configuration value from the admin.
I am sure that down the road, once more custom design packages are created, that some design packages would behave differently.