I am running Linux, the latest version of ubuntu with KDE4 installed. I have duel monitors, and they work just fine in X, and they both work in GNOME, but only one of them works in KDE4. I can't figure it out.

When I boot into KDE4 my left screen shows a desktop as it should, but my right screen just shows that classic X chain link fence background and is unusable for applications. I go to the screen tool, but it only shows the one screen.

So the monitor is working, the NVIDIA drivers are working, I just don't know how to use it in KDE4. I don't know if that makes sense or not.

The recommended way to run multi-monitor setups on Linux is with Xinerama (Called TwinView on nVidia cards and Big Desktop on ATi). You are currently in what's called multihead or dualhead mode where you are running one X server per monitor, Xinerama on the other hand shares a single X server across all monitors at once. The advantage of using only a single server is that you can freely move applications between each monitor unlike on multihead mode where applications are required to stay on the monitor that they open up on.

Hopefully the above info is enough to get you started with Google as I'm just about to run out the door. However, I'm sure someone else will post more detailed instructions later on how to do the conversion if you can wait for it.

Best bet in Ubuntu would be to install and run Grandr.

Krandrtray also works, but for it to pick up the VGA you first need to issue 'xrandr --output VGA --auto' in a konsole and then launch krandrtray.

I had a problem of this kind, too. What worked fine with KDE3.5 and Kubuntu 8.04 with two monitors, suddenly didn't work any more. xrandr and KDE settings couldn't help, but at the end I found out about the existance of a program called "nvidia-settings" that helped me to configure my two monitors as I wanted.

Must be a Kubuntu issue then. Both in Arch and MEPIS (upgraded to KDE4), I can easily use two monitors by using a randr tool. Maybe you can try to rename xorg.conf and then restart X with the external VGA plugged in. Then use xrandr / grandr / krandrtray to configure.

Sorry, I was mixing this up with the 2 Xsessions postings. I have moved my posts to this forum:

showthread.php?tid ... 6#pid15536

I want to thank everyone for your help. I was able to switch it to Xenerama mode, and now it works. I used the nvidia-settings and that did the trick.

It is now working great, and behaving as I very much wanted it to behave. I was using an older version of Linux before, and could never get Xinerama to behave well, so I stopped using it and switched to the two desktop mode. But I actually like the one desktop over 2 monitors much better.

Thanks again.