multi-head
dual head testing in XFCE
there were 2 test cases i used for dual monitors. these cases are described as follows...
mirroring
this would be for a presentation maybe. having the same image on both the main display, and a secondary display, such as a projector.
spanning
this would be where the desktop is actually extended onto both monitors making one big desktop.
mirroring tests
mirroring the display is quite simple with the included tool from XFCE/Xubuntu located in the menu under "settings" - "monitor settings". this package is LXrandr. http://packages.ubuntu.com/search?keywords=lxrandr
spanning tests
to enable, and manage dual head spanning, the only tool that worked for me (with a GUI) was arandr. http://packages.ubuntu.com/search?keywords=arandr the different displays were easy to find, configure and rotate using the GUI arandr.
arandr and 'monitor settings' in the menu have the same icons.
* between these 2 tools, we can cover whatever the end-user needs.
failed packages, and why
grandr failed. i couldnt enable spanning with it, and there were quite a few 'greyed-out' options.