Space bar navigation should stop at each article
While you're using the space bar to scroll along, Even if an article is 1.5 pages long, when you click SPACE again, the next article should stop at the top of the reading pane. Basiclaly a hybrid page\down and next article behavior.
Spacebar now doesn’t select next article until current one is fully read. That means that next article is always scrolled to top when it selected on the next spacebar press.
But I'm thinking that when article is 1.5 pages long it should not move next article to top on the next spacebar click. You've loose 0.5 page this way.
I'm thinking that it's probably worth to scroll 0.5 page (or how much is left) on last page down to see end of article but not switch to the next one.