[css-tables-3] Attempt to make repeated headers/footers work

You need to include the header as content rows if you cannot fit it
entirely in one page; same applies for the footer once you have
exhausted the body rows

Author: FremyCompany

css-tables-3/Overview.bs

@@ -2464,10 +2464,12 @@ spec:css22; type:property; text:display
 	<h3 id="repeated-headers">Repeating headers across pages</h3>
 
 		When rendering the document into a paged media, 
-			user agents must repeat 
+			user agents must try to repeat 
 				<a href="#table-header-group">header rows</a> and 
 				<a href="#table-footer-group">footer rows</a>  
-			on each page spanned by a table.
+			on each page spanned by a table 
+			where at least one header row or body row 
+			was considered to be a <a>content row</a>.
 
 		When the header rows are being repeated, user agents must 
 			leave room and if needed render the table top border.
@@ -2478,11 +2480,24 @@ spec:css22; type:property; text:display
 			<figcaption>Expected rendering of table with headers and footers fragmented across two pages</figcaption>
 		</figure>
 
-		When doing so doesn't leave enough space to insert at least one content row,
-			users agents must drop the repeated footer.
+		When doing so doesn't leave enough space to insert at least one <a>content row</a>,
+			users agents must drop the footer rows which are not content rows (possibly all of them).
 
-		When doing so still doesn't leave enough space to insert at least one content row,
-			users agents must drop the repeated header.
+		When doing so still doesn't leave enough space to insert at least one <a>content row</a>,
+			users agents must drop the header rows which are not content rows (possibly all of them).
+
+		
+		In a given fragmentainer, a table row is considered a <dfn>content row candidate</dfn> if
+			it hasn't been included yet in a preceding fragmentainer where it was considered a content row
+			(if no preceding fragmentainer exists, all table rows are considered content row candidates);
+		
+		In a given fragmentainer, a table row is considered a <dfn>content row</dfn> if it is in the set of
+			all <a>content row candidate</a>s from the table header, if any;
+			otherwise, all <a>content row candidate</a>s from the table bodies, if any;
+			otherwise, all <a>content row candidate</a>s from the table footer, if any.
+
+		User agents may consider all header rows and footer rows 
+			to form an unfragmentable block, to enable rendering the headers and footers the same way on each page.
 
 		<p class="advisement">
 			User agents may decide to extend this behavior to every fragmentation context,