In the above URL, second test (class "two"), there are problems with line wrapping with inline element margins. As I shrink/enlarge the window, the browser oscillates (for reasons I don't understand) between correct line wrapping and bringing the entire beginning of the inline element with negative margins onto the new line (rather than splitting it). An image of the bad behavior is at: http://www.fas.harvard.edu/~dbaron/tests/5505b This was originally reported in bug 5176, along with lots of other stuff.
*** Bug 5176 has been marked as a duplicate of this bug. ***
Sorry. The above URL should have been http://www.fas.harvard.edu/~dbaron/tests/nglayout/5505b
*** This bug has been marked as a duplicate of 3490 ***
Agreed. This is a duplicate of 3490.