Just to add, if the power manager is using xflock to lock the screen you need xscreensaver, xlockmore or slock, I think, for it to work.

xflock4 is just a bash script - so you can easily edit it to add other screen-lockers.

I use xtrlock so I added xtrlock to the list of lockers to check for.

#!/bin/sh
#
#  xfce4
#
#  Copyright (C) 1999, 2003 Olivier Fourdan (fourdan@xfce.org)
#  Copyright (C) 2011       Guido Berhoerster (guido+xfce.org@berhoerster.name)
#  Copyright (C) 2011       Jarno Suni (8@iki.fi)
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#

PATH=/bin:/usr/bin
export PATH

# Lock by xscreensaver or gnome-screensaver, if a respective daemon is running
for lock_cmd in \
    "xscreensaver-command -lock" \
    "gnome-screensaver-command --lock"
do
    $lock_cmd >/dev/null 2>&1 && exit
done

# else run another access locking utility, if installed
for lock_cmd in \
  "xlock -mode blank" \
  "slock" \
  "xtrlock"
  do
    set -- $lock_cmd
    if command -v -- $1 >/dev/null 2>&1; then
        $lock_cmd >/dev/null 2>&1 &
	# turn off display backlight:
	xset dpms force off
        exit
    fi
done

# else access locking failed
exit 1

This works for me:

xfconf-query -c xfwm4 -p /general/mousewheel_rollup -s false

Worked perfectly, thank you ToZ very much!!!
Thanks secipolla too!

I planned to switch over to Gnome3 "Debian flavor" (Redhat shipped with Gnome3 that I found quite unusable).
However it seems that the Xfce forum community really lives! I will likely stay with Xfce

(Accidentally rolling up my mouse button easily activates this thing...)

I'm on Fedora 17. I guess it's something new to Xfce 4.10 then.

Anyway, I remember reading other posts about folk having issues with this feature. And if you want 4.10 in wheezy, it seems it's in the experimental repository (probably only didn't come to wheezy because of the freeze process).

I would rather wait for a fix. Thanks for your help!

Anyway, I remember reading other posts about folk having issues with this feature. And if you want 4.10 in wheezy, it seems it's in the experimental repository (probably only didn't come to wheezy because of the freeze process).

I got a clue now about the failure to lock the screen.
Xfce currently has an issue of having more than one place to set the same thing and that may be confusing.
In the case of locking the screen when going to sleep it can be set both in the power manager and in Settings>Session and Startup, so try setting it in both (specially the latter).
Just to mention, a similar issue is that icons can be disabled for application menus in the appearance settings and that disables icons for the panel menu too even if it's set to show icons in its own properties.

Strange, I could not find any lock screen related options in Sessions and Startup.
Which distro are you using?

Good evening!

Settings>Window Manager and choose the button layout you want.

As for the bug, I've heard about that before but since I don't have that set up here I can't confirm. Try searching the net for it (and Xfce bugzilla too).

Thank you very much!

As for the bug, I've heard about that before but since I don't have that set up here I can't confirm. Try searching the net for it (and Xfce bugzilla too).

Any help would be appreciated!

Off topic: Xfce does not lock the screen when going to sleep or hibernate, even though I checked that in the power management settings. Any info on this before I file a bug to debian?