Actual results in Internet Explorer 8 beta 2: there is a green box alongside with a red box.
Expected results: there should be only a green box with NO red box alongside. There should be no red anywhere in this webpage.
Explanations: the generated content (green-box-100px-100px.png, 100px wide, 100px high, tall) should perfectly overlap and cover/mask the 100px wide and 100px high, tall red box created by the border of the tested <div>.
Firefox 3.0.3, Opera 9.62, Safari 3.1.2, Safari 4.0, Konqueror 4.1.1, Seamonkey 2.x all pass this test.
This bug has been reported at connect's IE beta feedback as bug 380412.
Update: this bug has been FIXED in Internet Explorer 8 Partner pre-RC1 build 6001.18343 released on December 11th 2008. Otherwise, Internet Explorer 8 Partner pre-RC1 build 6001.18343 PASSES this specific and particular testcase.