In all the above test cases, the box with grey border is floated, has a non zero margin-top, but zero margin-bottom. The container with aqua border is absolutely positioned, the one with yellow border has overflow:hidden, the one with magenta border has overflow:auto, the one with green border has the "easy clearing" fix, the one with red border is floated. In Opera 8, all containers correctly expand to enclose the float, but (except in the fourth case) the margin-top of the float is incorrectly replicated as margin-bottom?!
In the above test cases, the box with grey border is floated, with zero margin-top, and not zero margin-bottom. In Opera 8, all containers correctly expand to enclose the float, but (except in the fourth case) the margin-bottom of the float is ignored?!