[css2] Flushed out visibility property values

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%40823

Author: ianbjacobs

css2/visufx.src

@@ -244,12 +244,25 @@ class="propinst-visibility">'visibility'</span> property</H2>
 <!-- #include src=properties/visibility.srb -->
 
 <p>The <span class="propinst-visibility">'visibility'</span> property
-specifies whether the boxes generated by an element
-are rendered. Invisible boxes still affect layout (set
-the <span class="propinst-display">'display'</span> property
-to 'none' to suppress box generation altogether). This
-property may be used in conjunction with scripts to
-create dynamic effects.
+specifies whether the boxes generated by an element are
+rendered. Invisible boxes still affect layout (set the <span
+class="propinst-display">'display'</span> property to 'none' to
+suppress box generation altogether).  Values have the following
+meanings:</p>
+
+<dl>
+<dt><strong>visible</strong>
+<dd>The generated box is visible. 
+<dt><strong>hidden</strong>
+<dd>The generated box is invisible, but still affects layout.
+<dt><strong>collapse</strong>
+<dd>Please consult the section on 
+<a href="tables.html#dynamic-effects">dynamic row and column
+effects</a> in tables.
+</dl>
+
+<P>This property may be used in conjunction with scripts to create
+dynamic effects.
 
 <div class="html-example"><P>
 In the following example, pressing either form button invokes a