I'm running the enterprise evaluation (Build 9200) of Win8 and VirtualBox 4.2.4 r81684 and my actual display is 1920x1200. When I use the host-F key to enter full screen mode, the best I can configure in Windows is 1600x1200 which is fine, but I'd rather get the whole screen in play rather than see a letter boxed OS.
First I tried running the Install Guest Additions but windows didn't run any installers that I could see as described in the VirtualBox documentation.
I have allocated the maximum amount of RAM (256MB) to the Display Video Memory and don't see any way to load drivers after searching the VirtualBox documentation. I can enable or disable 3D and 2D Acceleration and these settings do not affect the outcome. I've set the monitor count at 1 and not enabled the Remote Display server. Since special things happen in each corner, Fitt's law is making it a pain to hit the targets for the corners to explore the UI whether I'm running the OS in a window or full screen.
Am I missing a setting somewhere in Windows or VirtualBox to fill in my true display resolution since it's not sensing it correctly? I'm open to hacking a driver file or other steps if needed to get the correct resolution set.