z-index not working with fixed positioning

Question

I have a div with default positioning (i.e. position:static) and a div with a fixed position.

If I set the z-index

Answer 1

When elements are positioned outside the normal flow, they can overlap other elements.

according to Overlapping Elements section on http://web.archive.org/web/20130501103219/http://w3schools.com/css/css_positioning.asp