STEPS TO REPRODUCE 1. Have a block of width 2x. 2. Put a float inside it of width x. 3. Put an overflow:hidden block inside the block of width x+1. EXPECTED RESULTS overflow:hidden block under float. ACTUAL RESULTS overflow:hidden block next to float. TESTCASE http://www.hixie.ch/tests/adhoc/css/box/float/root-formatting-contexts/001.html
*** Bug 295069 has been marked as a duplicate of this bug. ***
*** Bug 350474 has been marked as a duplicate of this bug. ***
When we check in the fix + tests, we should check "auto" in addition to "hidden" for the overflow value.
I think this has been mostly fixed. However, this particular testcase still shows the problem, because for some reason the fix isn't working when the replaced element or element with overflow:hidden is at the very top of the block.
Fixed by bug 478834.