Actually, when using future/scheduled posts, there is what I consider to be a bug.
If the future scheduled post (draft) uses a category that was never used before, once it gets changed to ‘Published’ status, you have to manually highlight the new category in the Slider settings to get the newly published post to show on the slider.
It’s pretty annoying, as there is no way to highlight the new category in advance of the post being published.
For what it’s worth, I’m still using v 2.2.0