Package: virtualbox-guest-x11
Version: 4.3.31-dfsg-1+deb8u2
I suggest the package recommend x11-server-utils, since without xrandr the
guest can not adjust to changing display sizes such as switching the guest to
full-screen or changing the geometry of the window on the host system.
Background: Running VirtualBox from a Debian 7 amd64 host I created a Debian 8
(jessie) VM and installed mythtv and a minimalist X server (since myth doesn't
work over remote X). I installed virtualbox-guest-{dkms,utils,x11}. I
discovered that X always ran at 800x600, even if I started it after making the
VM full-screen (1920x1200).
After a long period of experimentation I realized xrandr might allow me to
resize the display. It did, and the guest display now resized automatically
when the host window size changes. I assume that xrandr was the crucial
element (note the randr libraries were already installed before this), but the
only thing that is certain is that installing the x11-server-utils package
cured the problem.
P.S. The README.Debian appears badly out of date. No editing of xorg.conf is
necessary and running the x11config.pl script named in the README produces an
error that a file, I think xorg.conf, is not found.
