I have two screens connected to my computer. I can reflect the screen contents so both screens shows the same thing, but i can't get extended desktop:
I have no alternative to choose "extended desktop" or something.
My graphic card is a Radeon HD 7770, and the driver is from X.org.
I Use Ubuntu 13.04 with Xfce 4.10.
I believe you need to either:
1. Install the proprietary catalyst drivers and use the tools that come with that driver, or
2. For the opensource drivers you need to use xrandr (see: https://wiki.ubuntu.com/X/Config/Resolution)
...will show the current xrandr settings and identify your monitors by name (e.g. VGA1, VGA2, etc).You can then use a command like:
xrandr --output VGA1 --left-of VGA2
...to extend the desktop.
Thanks! Option 2 worked.
arandr is a nice GUI to xrandr if you prefer graphical tools.
BTW, I always add a keyboard shortcut to a script that resets display setup (to be used in the case something weird happens):
xrandr --auto xfce4-panel -r xfdesktop --reload