http://images.google.com/imgres?imgurl=http://operachic.typepad.com/.a/6a00d83451c83e69e201053587bced970c-500wi&imgrefurl=http://operachic.typepad.com/opera_chic/angela_gheorghiu/&usg=__CBtE94t6WyIJMt6TfkriaWEv7Gs=&h=594&w=392&sz=86&hl=en&start=25&um=1&itbs=1&tbnid=o-8p9wbFCnCHrM:&tbnh=135&tbnw=89&prev=/images%3Fq%3DQueen%2BRania%2BAl%2BAbdullah%26start%3D20%26um%3D1%26hl%3Den%26safe%3Doff%26client%3Dsafari%26sa%3DN%26ndsp%3D20%26tbs%3Disch:1 Enable flat frames for the Mac OS X build, and you can't scroll this page.
I can confirm this. Also note, that it is possible to scroll the page if you select text with the mouse.
We need to ignore overflow: hidden; for the owner frame when enabling frame flattening
The page in concern shows a header plus an iframe containing the original site When using iframe flattening the main frame changes it size to the size of the "header" plus the page shown in the iframe, but as body of the mainframe has overflow: hidden, it is unscrollable. Turning that off using Web Inspector shows that that is the issue at hand.
Really this is a design mistake in the page, as they've set overflow:hidden unnecessarily. I'm not quite sure how you could decide to scroll this page, since the author has just plain told you not to.
I'm inclined to believe this is behaving correctly.
Similar to other bug - frame flattening is code. Do we need anything here? https://github.com/WebKit/WebKit/commit/37224f042c178a094cc2287dee595345bc89f687