How can I make a gnome panel only appear if I have a second monitor hooked up?

Question

I have a laptop with Ubuntu installed on it and I'm constantly switching from just my laptop to also having a monitor. When I'm using the laptop screen and monitor, I have a panel on each monitor that shows the windows open for that monitor. If I switch to just using the laptop screen, then both panels end up on the same screen. How can I configure one of the panels to only show up if I have two monitors? Or can I at least "suspend" one of the panels somehow so I don't have to set it up the way I like it every time I switch?

Answer 1

Try setting the screen option for this panel via gconf-editor.

Run gconf-editor and navigate to the panel options at /apps/panel/toplevels/panel_1/ (your panel name may vary slightly). You should see an option screen as shown below. Try configuring this to your liking.

I'm not sure this will work, as I have a feeling that when you switch to using just the laptop screen, this value is automatically changed to the available screen. It's worth a shot.

If you use Xinerama, there's also an option to configure the monitor the panel appears on.

If none of these work, I'd suggest you enable auto-hide, and set a very low auto_hide_size so the panel is barely visible when you switch to one screen.

I haven't researched this yet, but if there is a command-line way to modify these values, I'd just use a script to tweak these values so the panel is hidden when I want it.

Answer 2

Here's what I did (on Ubuntu 10.04):

To fully hide the panel, you can set monitor to -1 using gconftool-2. The only caveat is sometimes you have to kill/restart gnome-panel after changing the monitor setting. This should do the job (killall without rerunning gnome-panel doesn't always bring it back):

gnome-panel --replace

There is a blog post here with a simple script that you can hook onto nvidia-settings or gnome-display-properties:

http://blog.zoomeren.nl/2010/03/05/a-gnome-panel-for-each-connected-monitor/

Since I use Nvidia, I did nvidia-settings -tq TwinView to check if TwinView is on, but you might not be able to tell the difference between two and three monitors.

Answer 3

GConf includes a command line tool, gconftool-2. You can use the gconftool–2 command to perform the following tasks:

• Set the values of keys.
• Display the values of keys.
• Install schemas from schema definition files when you install an application.

For example, use the following command to display the values of all keys in the /desktop/gnome directory and subdirectories.

gconftool-2 --recursive-list /desktop/gnome