ah, I am sorry, 2-3 versions ago was support for s-pen rewritten, but documentation, it is still old ;( But do not worry, it work, only a bit differently. Now you can use longpress and double tap gestures which nicely replace these options. In mouse options you can set what will be main (default) mouse action (mouse button) if you touch the screen. It was changed because finger and spen is in android system different hardware and there were various annoying blockings which prevent it work well together, but with gestures you can control spen very well.
I update docs over hollyday
Edit : mouse option was updated, will continue on other sections as soon as possible