"For example, I was using OpenSolaris 2008.11 and VirtualBox
seems to create a "virtual" monitor where the operating system
(specifically X) is unable to read the monitor's EDID information
to obtain supported resolution information (among other things). As
a result of this, by default X assigns 800×600@60 and
640×480@60 as supported display formats. When you are working
on a wider screen that supports something larger, this makes for an
uncomfortable computing experience; especially with limited
graphical space on the virtual client.
"In my case, my laptop's wide screen has a native resolution of
WXGA (1280×800). So I had plenty of extra room to work with.
WhileVirtualBox allows you to fullscreen a virtual client, I like
to multitask and this would limit my multitasking. I wanted to
create a display configuration that would utilize most of the
1280×800 while allowing me to manage multiple other
applications/windows on my host operating system."