revising text based on Anton Prowse's message, adding examples

Author: howcom

css3-multicol/Overview.src.html

@@ -388,10 +388,8 @@ <h2>The multi-column model</h2>
 <p>Column boxes are block container boxes. That
 is, column boxes behave like block-level, table cell, and inline-block
 boxes as per CSS 2.1, section 10.1, item 2 [[!CSS21]]. However, column
-boxes do not establish containing blocks for elements with ''position:
-fixed'' or ''position: absolute''. <!--Percentage values that are calculated
-relative to the containing block height are calculated based on the
-multicol element's height, not the column box's height.-->
+boxes do not establish block container boxes for elements with ''position:
+fixed'' or ''position: absolute''. 
 
 
 <div class=example>
@@ -868,7 +866,7 @@ <h3>Stacking context</h3>
 
 <p>All column boxes in a multi-column element are in the same stacking
 context and the drawing order of their contents is as specified in
-CSS 2.1.
+CSS 2.1. Column boxes do not establish new stacking contexts.
 
 
 <h2>Column gaps and rules</h2>