I love Mac OSX, but this is by far the most annoying bug I have ever dealt with... And it's been going on for years.
When I turn on my computer, I have it set to open Calendar and Messages in Desktop 1, FireFox on Desktop 2, Mail on Desktop 3 and Reminders and Notes on Desktop 4. Pretty simple stuff except that for some reason, they all like to shuffle around.
And it's not just one computer. I have 2 iMacs, both on El Capitan, set to do the exact same thing. I don't feel like it's a tall order to want everything to open exactly where I assigned them.
