Full-screen apps save switching points

Question

I get a really annoying side effect occurring in osx, which seems to be unable to find a way to fix it: for some reason, full-screen apps keep switching positions. For example, if I have Safari, Mail and Xcode are open in full screen, in that exact order, they will be swapped every time (for example, Xcode sometimes moves to the left, so this scroll left will lead me to Safari instead of mail). The order of these applications is important for performance, and it gets very confusing when you have 6 of them, and spam mail goes from place 6 to place 2.

Any ideas on how to make this switchover stop?

Answer 1

Go to "System Preferences"> "Mission Management" and make sure that "Automatic reallocation of spaces based on recent usage" is unchecked.