VirtualBox and D3D

I have been working with VirtualBox for a while now. Until today, I assumed D3D is enable as I had ticked the box for D3D support while I was installing the Guest software. However today when I was upgrading my VirtualBox to 4.0, I came across this error message said I couldn't enable D3D supports as I weren't in Windows Safe Mode. After Google this error, I now realize that in order to get D3D to work, I have to install the Guest under Windows Safe Mode. VirtualBox is a great free virtualization solution, however, I am surprised it take this long to include this little error message ... (okay, I admit didn't read the full manual) ...