offscreen rendering with Xvfb: strange results, only black images. (Fedora 18, mayavi 4.3 installed with rpm, or installed from the source on github),

(Sorry that I'm not quite sure whether it is the right place to report this issue.)

I render some images using `Xvfb` according to the tips here http://docs.enthought.com/mayavi/mayavi/tips.html#offscreen-rendering.

It worked perfectly under Fedora 17, mayavi 4.2.
But on Fedora 18, with all package updated, and
- Mayavi.x86_64 0:4.3.0-2.fc18., installed with yum,
- Mayavi 4.3, installed from source on github.

for these two cases, the saved images are always black.

After removing mayavi 4.3, and installing mayavi 4.2 from rpmfind.net, there is no such black image problem any more.

Hongying