[css-tables] Specified rendering of visibility: collapsed table-track/groups & spanners

Author: Greg Whitworth

css-tables-3/Overview.bs

@@ -2577,6 +2577,25 @@ With a table-internal box as non-containing block parent</h3>
 			: outset
 			:: Same as <code>groove</code>.
 
+	<!--——————————————————————————————————————————————————————————————————————————-->
+	<h3 id="visibility-collapse-rendering">Rendering for visibility: collapse</h3>
+
+	When a table part has <a href="http://www.w3.org/TR/CSS22/visufx.html#visibility">visibility: collapse</a> set, the rendering is handled
+	differently depending if it is on a <a>table-cell</a>, spanning <a>table-cell</a>, or a <a>table-track</a>/<a>table-track-group</a>.	
+
+		<h4 id="visibility-collapse-cell-rendering">Rendering a visibility: collapse table cell</h4>
+		As stated in CSS 2.2, if a <a>table-cell</a> has its visibility set to that of collapse, it is rendered the same as
+		if it had <a href="http://www.w3.org/TR/CSS22/visufx.html#visibility">visibility: hidden</a> set.
+
+		If the <a>table-cell</a> is spanning more than one <a>table-track</a>, and the <a>table-track</a> is set to 
+		<a href="http://www.w3.org/TR/CSS22/visufx.html#visibility">visibility: collapse</a> then the
+		cell is clipped to its border box.
+
+		<h4 id="visibility-collapse-track-rendering">Rendering a visibility: collapse table-track or table-track-group</h4>
+		When a <a>table-track</a> or <a>table-track-group</a> has <a href="http://www.w3.org/TR/CSS22/visufx.html#visibility">visibility: collapse</a>, 
+		none of backgrounds, borders or outlines that are contributed by the cells within the given <a>table-track</a> or 
+		<a>table-track-group</a> are painted.
+
 
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