When switching buffers, emacs seems to prefer buffers that aren't already visible.
For example, normally when I'm editing and switch to another file, when I
C-x b, the buffer I was last in is at the top of the list in
helm-mini, which often is what I want. However, if that file (the original one that I switched from, that I often want to switch back to) happens to be open in another window, it'll be at the bottom of the list. It seems to assume I'll most likely want to switch to a buffer that isn't already open, but that's not really the case for me.
How can I stop this, so emacs behaves the same whether or not it's already visible?