totally collapsed

From: Andrew Fedoniouk <news@terrainformatica.com> Date: Thu, 1 Jul 2004 22:38:23 -0700 Message-ID: <000e01c45ff6$cac4dfb0$0201a8c0@ATHLON> To: <www-style@w3.org> · This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 27 April 2009 13:54:31 GMT

Gentlemen, I need your help,

I cannot explain to myself: 

why here 

 p { border: blue solid 1px; }
<body>
<p>paragraph</p>
</body>

margins of the paragraph are collapsed ,

and here

 p { border: blue solid 1px; margin:1em }
<body>
<p>paragraph</p>
</body>

margins of the paragraph are not collapsed.

Any sacred knowledge to share?

I am trying to use rules from: 
http://www.w3.org/TR/CSS21/box.html#collapsed-through

I am testing this in Internet Explorer and Gecko. 

Thanks in advance,

Andrew Fedoniouk.
http://terrainformatica.com