Comment 6 for bug 306215

Alvin, the problem isn't when using File->Export Bitmap. When going to print you are given the option to change the rendering backend from vector to bitmap.

When printing with the backend set to Vector, the shape is not printed at all.
Although setting the backend to Bitmap, I get the yellow circle with a black background.

As such there is an issue whichever backend you use. Its probably more noticeable with the bitmap one.

Actually using Export Bitmap is what I have been using as a workaround.