VirtualBox 3D acceleration removes the top bar on windows?

I've just done an install of Zorin OS 9, and it's running really well. Everything installed fine and I got the VirtualBox Additions installed. However, I went to turn on 3d acceleration, and I noticed something strange. 3D Acceleration makes everything run really smoothly, but it removes the top bar on app windows.

No 3D Acceleration: i.imgur.com/EWsyenW.png

With 3d Acceleration: i.imgur.com/IaMupBk.png

When it is on, I can't move the folder window, but the terminal will still move.

Anyone have any idea why this is happening, and what I could do to fix it?

Can you access CompizConfig Settings Manager in VB mode when 3d acceleration is on? I am wondering if it is to do with the 'Windows Decoration' settings - also have you made host to client 'both ways' - sharing clipboard/system resources etc?

I agree with swarf. It is not a VB problem, but a compiz problem. Zorin has the compiz settings enabled by default (for PCs/GPUs that can handle it). So if the vram of a GPU is not adequate (like in a VB experience), you may experience phenomena like this. The highest vram offered by VB is 128mb. Have you set it to maximum?
This is why you don't have problems when the 3D is disabled.

So, as Swarf said, first thing to do is to open the compiz config settings manager and enable the "windows decoration". Log out/in and see if that helped.

I also know a trick to increase the vram in VB from 128 to 256mb.

Hi, and thanks for your help! (Sorry for the late reply!)

VRAM is set to 128 MB. And when opening Compiz Config Settings, Window Decoration is already enabled. Disabling it did not help either. Is there another tweak I can do?