[TriLUG] C-A-D, xubuntu, xfce4, xflock4

[Tom Roche]

0 How to remap C-A-D in xubuntu-9.04 to be semantically equal to
  hitting the icon @ upper right of desktop?

1 How to fix/debug whatever's making my screen take forever to lock?

What I mean:

This summer I finally quit putting up with winxp (cygwin definitely
makes that easier!) and put a linux (

xubuntu=9.04
kernel=2.6.28.13-generic
GNOME=2.26.1

) on my daily-use ThinkPad. (Wubi made that trivial--the major
difficulty was learning how to share my emacs and firefox configs with
winxp.) I'm mostly happy, and will probably make a linux partition
shortly, but a few things still bug me.

One is the semantics of C-A-D (aka "Ctrl-Alt-Del" OR "Control-Alt-
Delete"). On xp it pops up a dialog not unlike the one I get with
xfce4 when hitting the icon @ upper-right corner of screen (a red
arrow pointing right, past something like an open door): options=
logout, restart, suspend, etc. On xubuntu I get a screenlocker that's
taking 30 sec to put up its dialog.

The direct problem with my current C-A-D problem appears to be the
latter entry in

$ find ~/.config/ -type f | xargs fgrep -ne '"<Control><Alt>Delete"'
> ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml:7:      <property name="<Control><Alt>Delete" type="empty"/>
> ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml:14:      <property name="<Control><Alt>Delete" type="string" value="xflock4"/>

So my first question is: with what command should I replace "xflock4"
above to get the upper-right-corner-icon semantics? (Extra credit for
something that would run a dialog with a screen lock option included.)

Secondly, how can I debug or fix whatever's causing xflock4 to take so
long to setup? Or is there another screenlocker I should try?

TIA, Tom Roche <Tom_Roche at pobox.com>