If I move between split windows as in this SO answer https://stackoverflow.com/a/4671868/461887
C-x o
It closes the left hand side buffer/split when doing this. I just want to hop between the splits not close the current split.
How do I do this?
Make sure you are hitting the letter 'o', not the number 0. 0 will close the current window, and 'o' will switch to other window. ('window' in emacs terminology is what you are referring to as a 'buffer' or 'split')
If that doesn't work, try loading emacs with '-q' at the command line which will disable loading of any customizations in your initialization file that might be interfering with emacs' default keybindings.
emacs -q
You can also try C-h b
which will pop up a buffer which describes all of your keybindings - search this for C-x o
to see what it is bound to.