nicols@nicols:/usr/share/sddm/scripts$ diff -u Xsession.dpkg-old Xsession
--- Xsession.dpkg-old   2015-08-24 12:50:21.000000000 +0200
+++ Xsession    2015-10-20 21:24:20.000000000 +0200
@@ -20,7 +20,7 @@
       . $HOME/.profile
     fi
     ;;
-  */zsh)
+*/zsh)
     [ -z "$ZSH_NAME" ] && exec $SHELL $0 "$@"
     [ -d /etc/zsh ] && zdir=/etc/zsh || zdir=/etc
     zhome=${ZDOTDIR:-$HOME}
@@ -89,9 +89,6 @@
   "")
     exec xmessage -center -buttons OK:0 -default OK "Sorry, $DESKTOP_SESSION is no valid session."
     ;;
-  failsafe)
-    exec xterm -geometry 80x24-0-0
-    ;;
   *)
     eval exec "$session"
     ;;