Bottom margin unexpectedly not rendered in Internet Explorer 8

The relevant CSS code for this page is:

    body
    {
    margin: 0;
    }

    #mainWrapper
    {
    border: green solid medium;
    margin: 100px;
    }

Actual results for this webpage testcase:
- in IE 6 and in IE 7, there is no bottom margin below the green bottom-border of this webpage
- in IE 8 beta 1, there is no bottom margin below the green bottom-border of this webpage.

Expected results:
there should be a 100px margin surrounding all 4 sides of the green bordered box in this webpage. So, there should be a 100px bottom margin below the green bottom-border of this webpage.

Reference:
"[A margin] percentage is calculated with respect to the width of the generated box's containing block. Note that this is true for 'margin-top' and 'margin-bottom' as well."
CSS 2.1, section 8.3 Margin properties

Firefox 2.x, Firefox 3, Opera 9.26, Opera 9.50, Safari 3.1, Konqueror 3.5.8, Seamonkey 1.x, Seamonkey 2.x, NS 7.0, NS 7.2, K-meleon 1.x, Epiphany 2.22, Galeon 2.0.2, Hv3 TKHTML alpha 16, Amaya 10.0 build 20080229 all pass this test.

Credit must go to Dorayme for posting this issue in comp.infosystems.www.authoring.stylesheets forum discussion newsgroup the IE 7 Margin Problem message and for his No Expected margin bottom in IE 7 testcase

The relevant CSS code for this page is:

    body
    {
    margin: 0;
    }

    #mainWrapper
    {
    border: green solid medium;
    margin: 100px;
    }

This bug has been reported at connect's IE beta feedback as bug 344804.

Update: This bug has been FIXED in Internet Explorer 8 beta 2 (build 6001.18241) released on August 28th 2008. Otherwise, Internet Explorer 8 beta 2 PASSES this specific and particular testcase.