The following test started to produce image difference since r73423: fast/repaint/positioned-document-element.html Dave, could you take a look at this?
Created attachment 76009 [details] positioned-document-element-expected.png
Created attachment 76010 [details] positioned-document-element-actual.png
We don't have any platform specific expectation for the following test case anymore - searched via 'searchfox.org' (wubkat). Marking this as 'RESOLVED CONFIGURATION CHANGED'.