When using zsh in gnome-terminal in 5.8.2 several
keybindingings don't work properly (eg. tab completion or
arrow keys, instead of doing something it just shows
what the key would normally do). gnome-terminal+bash is
fine, so is xterm+zsh or console+zsh.
Removing the setuid bit from gnome-pty-helper fixed the problem.
Basically the tty's got owned by root in /dev/pts so the user
didn't have the permission to access them.
Actually I don't think a gnome-pty-helper is needed at all with UNIX98
pty's. Also you could call the fact the tty gets shown as ttypX
instead of pts/X in utmp in gnome-terminal a bug (since the tty
really is a pts/X)
These problems were fixed prior to 6.0.