I enabled post preview here, so when you are in a topic listing and hover (about 1 second) over the topic subject, you get a short preview.
We have had this since 1.0, so the changes are really behavioral/cosmetic. Also this was one of the former Jquery functions redone in vanilla JS
First it now shows the preview above the hover point IF there is room, otherwise below. This is opposite of what it was. Since most users work down the list, having the popup above does not block your access to the next list item to hover over. Previously if you want to go to the next item you had to hover away to clear the hover in order to gain access to the next item.
Second, it used (well still does) cut the post after xx number of characters, but it also now has a max height on the hover preview with the same fade away that we use on long quotes. The previous behavior was to always show xxx characters, which when you had an inline image or two it could become a very large popup.
Third It now has a defined min-width so it provides a consistent view/layout. Previously it was more like a tool-tip, where the width could be very short and kind of look odd.
Anyway check it out if you want :D
I guess it's a topic preview rather than a post preview since only the former is shown.
Never noticed that, I just checked and works as you describe it.