With the FKMS driver re-enabled (with it off you lose 3d acceleration), you get one frame buffer, but you can make it incorporate the two displays. Go to the screen configuration utility, and you will see just one display, but that is in fact one over the other. CLick and drag the display around and you will see its actually two displays, and you can then set them up as you want, including different orientations, gaps between etc.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
"My grief counseller just died, luckily, he was so good, I didn't care."