LXDE on multiple X11 screens -- how?

[grant.edwards]

I'm trying to figure out how to use LXDE on a machine with three
X11 screens[*] (DISPLAY values :0.0, :0.1, and :0.2).

When I start LXDE (using the default Gentoo configuration) I get
default wallpaper on all three screens, and screen :0.0 works as
expected.

But, the other two screens don't seem to have any window manager,
panels, or root menus. Moving the mouse onto the other two displays
results in the X11 default "X" cursor, and mouse buttons all do nothing.

I manually started openbox on screens :0.1 and :0.2, and that worked.
However, the root menus are different than on :0.0. I presume that's
because something other than openbox is generating the root window
menu on :0.0? pcmanfm?

I changed the wallpaper using desktop settings, and it only affected
:0.0.

I tried creating new panels the normal way, but there's nowhere to
specify which screen the panel is for. There is an input widget for
"monitor" but that's grayed out (presumably because the screen on
which lxpanel is running has only 1 monitor). I looked at the
documentation for the lxpanel config file, and couldn't see anywhere
to specify a screen.

I tried manually starting lxpanel on the other two screens, but all it
does is complain there is already an instance running and then exits.

How do I place panels on screens :0.1 and :0.2?

I also tried manually running pcmanfm on :0.1 and :0.2, but it just
opens windows on :0.0. If I can't get pcmanf to handle displays :0.1
and :0.2, can I at least get rid of it for :0.0 so that at least all three
screens behave the same?

The openbox developers made a conscious design decision to handle
multiple screens using multiple instances, and that seems to be
working.

It's the LXDE part that I can't figure out. It appears that the LXDE
programs support neither multiple instances nor multiple screens in a
single instance.

Can anybody point me to any documentation or hints on how to use LXDE
on a multi-screen setup?


[*] Just be clear: I have a single X11 server with three separate
screens with different DISPLAY values. That is different than
having a single X11 screen spread across multiple physical
monitors (which is what you get with twinview and xinerama and
xrandr). In my setup each screen is a separate desktop, each of
which has it's own set of virtual desktops (aka workspaces). I
typically run 4 virtual desktops (workspaces) per screen.
Switching workspaces on one screen does not affect the other
screens.

Yes, that's the way I like it. And no, I'm not going to switch to
a single-screen/multiple-monitor setup.

[grant.edwards]

Here's the solution I ended up with:

• Get rid of pcmanfm (doesn't work with multiple screens), and use
  the root-window menus provided by openbox. [I'm using
  obmenu-generator to generate the right-click menu.]

• Replace lxpanel (doesn't work with multiple screens) with tint2.

After crossing off the list the other pieces of LXDE that provided
features I didn't want, I ended up with 3 packages:

openbox
obmenu-generator
tint2

tint2 and obmenu-generator replace 30+ packages required for LXDE,
which had quite a few pieces I didn't need and a lot of
dependencies[*].

I guess it turns out that I didn't really want a "desktop
environment", just a decent window manager and some panels.

[*] OK, I know that's not "a lot" by Gnome or KDE standards, but it is
for somebody who once wrote X applications that ran directly on
top of Xlib. Yes, I'm that old. ; )

[Rex Bouwense]

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