I noticed that you can select vertices through other objects. Here is an example to show what I mean:
I have a cube partially inside a sphere. When I do a circle select when the back vertex is hidden behind the sphere...

Both vertices, including the one that was hidden by the object, are selected.

Is there a way to prevent this behavior?
EDIT: I tried the "limit selection to visible" option but it didn't work... I believe this case is different because it is selecting through a different object, not just itself.