Text and images look like they've been rendered twice, slightly offset (see screenshot).
Created attachment 18818 [details] Screenshot of the doubling effect.
The patch on bug 17107 fixes this issue. Dan commented on IRC that he would expect the double painting to happen at the same location like the instance in bug 17107 rather than offset like seen here. He may want to investigate this a little more before marking this as a duplicate.
Created attachment 18819 [details] Reduction
Thanks for the reduction, Mark. It looks like WebKit is correct in making the text field clear the float based on the in-flow position of the div, so the only problem is the extra painting, which is bug 17107. *** This bug has been marked as a duplicate of 17107 ***