[CSS22] Edited the text to include the erratum for 'z-index: auto':

fixed-positioned elements always create a stacking context.

Author: bert-github

css2/visuren.src

@@ -1959,8 +1959,8 @@ class="propinst-z-index">'z-index'</span> property specifies:
   <dt><strong>auto</strong>
 
   <dd>The stack level of the generated box in the current stacking
-  context is 0. The box does not establish a new stacking context
-  unless it is the root element.
+  context is 0. If the box has 'position: fixed' or if it is the root,
+  it also establishes a new stacking context.
 </dl>
 
 <p><em>In this section, the expression "in front of"