virtualbox.org

Upgraded to vbox 4.3.6 today, running on 15 inch Macbook pro with retina display.

My guest is running the following:

• Linux 3.2.0-55-generic (Ubuntu) with 4GB VM and 4 cores
  Updated to latest packages and Kernel
  Re-built and installed latest guest additions

Now the following have stopped working:

• No full screen mode on guest (used to run 1920x1200 - Mac screen or 2048x1152 - external screen Samsung SyncMaster 2343)
  No copy-paste between host and guest
  Screen show black borders on either side
  Sometimes see a second ghost cursor on the
  Switching between Mac and external display the display sometimes freezes
  Mouse cursor very jerky and almost unusable

My system is completely unusable, help is there any way to go back to 4.2.x release of vbox which used to work fine before today

Interesting after posting this question and wasting the whole day.
I just tried switching the host back to default retina resolution, stopping the guest(power off) and starting the guest back and then switching the resolution to 1920x1200 scaled mode from native retina -> 1920x1200 followed by switching the guest to full screen mode. Now it seems to be working and able to view at my external display resolution of 2048x1152

Perhaps there is some bug in the resolution handling code, it seems to be able to deal with resolution change but not initial resolution discovery, earlier had rebooted both guest and hoist numerous time all while the host was set to 1920x1200 mode that seems to not help at all.