I often start X with one screen then use xrandr 1.2 to add another screen. When I do so, xfdesktop fills both screens with what used to be the wallpaper image on a single screen, even though I do not turn on the option "extend a single background to all monitors" in the settings. If I turn that option on and then off right away, then the image moves to one of the two screens, but the other screen does not have an image. I then need to run "xfdesktop -reload" to get the two screens to each show their own image.
Unfortunately gtk doesn't support randr 1.2 properly yet; gtk 2.14 will. Your particular case might be able to be worked around without too much difficulty... There's no 'screen-added' or 'screen-removed' signal on GdkDisplay at present, but xfdesktop could recheck the number of screens when GdkScreen's 'size-changed' signal gets emitted. Might put in a workaround, might wait for gtk 2.14. Depends on available free time.
Implemented in trunk; requires gtk 2.13 or above.
Thank you!
Created attachment 2509 Image I'm using xfdesktop 4.6 with gtk 2.16, and i'm still having this issue of two images when i run xrandr --output VGA --mode .... . attached a picture.