Comment 6 for bug 132154

This problem is related to an Omniweb's bug originating from an old Safari/Webkit bug.

Quote from http://www.quirksmode.org/bugreports/archives/safari/index.html
"In Safari the entire body disappears if you set position: relative on the HTML first, and then on the BODY. (...)
Workarounds include using quirks mode, or playing it safe and avoiding setting positioning to the html element."

Despite the fact that the latest Omniweb announces itself as AppleWebKit/420+ (newer than the latest Safari),
this bug had not been fixed.

I set "html { position: static }" in css, which seems to solve the problem without affecting rendering in other browsers.