Usenet Explorer

I open up articles list, press Alt+S and nothing happens

But when i use my mouse and point cursor over Select related articles and press LMB everything is Ok..

Does anyone else have this?

The algorithm is heuristics, the focused entry is taken as the reference, then it looks for "similar" entries in the group, but also avoiding selecting in too generic way, it was added even before collections. If there are some apparent underselections it can be changed, but if the change would result in overselection for many other cases it is better to leave it then.