When I move the mouse pointer within a list of threads small pop-up windows with a blue background appear, showing a preview of the beginning of the text within the respective post.
Whenever I scroll the page with the mouse wheel when any blue pop-up is on the pop-up disappears, but the former contents below it are not restored, leaving just a grey footprint of the pop-up.
Konqueror does not show the problem. Epiphany works fine too, but behaves different. The blue window stays when scrolling and changes to the next one when the mouse pointer reaches the next post.
To me it means that different browsers act different on this feature. Some maybe not following the standard as intended (browsers have some leeway how to implememt things). But as you post this in Forums Feedback > Forums Comments/Suggestions, I guess you think it is a bug in the forums software.
I guess you think it is a bug in the forums software.
In fact I did not guess anything except that the problem could already be known because I am not the only one using seamonkey.
In the meantime I found that seamonkey shows the same phenomenon on other websites too. This makes it probable that there is nothing wrong with the HTML coding of the openSUSE forums. All the better.