Why do full-screen applications change their order in Mission Control? How are fullscreen apps organised? This is usually my workflow:

Dashboard / Desktop / Safari / Pages


I sometimes go to Pages and type some things and go back to Safari, and then I find that it becomes like this:

Dashboard / Desktop / Pages / Safari


It has shifted location for some reason.

Why?
Uncheck it if you must :). Then it will retain 'as launched/created' order.