A while ago I noticed that shift space no longer seemed to scroll backwards in pdf-view-mode (nor any other mode where it would make sense). I could swear it used to work fine, and it even works on my windows machine. However I've now tried emacs 28 & 29 (my own config and -q in GNOME, a terminal emulator with --nw and a tty and all seem to have the same issue.

If I try to bind S-SPC to anything, then C-h k still only sees SPC being pressed, so it seems like emacs is just ignoring the shift key being held.

Anyone else had this problem? It's not the most serious thing in the world, but it is puzzling.