I also see this rather often when I use xrandr with compiz. The desktop cube rotates in the top-left area the size of my laptop screen, while the rest is not necessarily black -- often it contains a desktop image from when I last used dual-head, i.e. whatever happens to be in the video memory.
I also think bug 206998 might be a duplicate of this one.
I also see this rather often when I use xrandr with compiz. The desktop cube rotates in the top-left area the size of my laptop screen, while the rest is not necessarily black -- often it contains a desktop image from when I last used dual-head, i.e. whatever happens to be in the video memory.
I also think bug 206998 might be a duplicate of this one.