spec/css3-box: edited

Author: aprowse

spec/css3-box.txt

@@ -55,6 +55,8 @@ Problem: difficulty in inserting new rules to modify how the containing block of
 Problem: difficulty in restricting attention to only those boxes for whom the container will establish the containing block \\
 Problem: difficulty in removing boxes from the set of potential containing block–establishing boxes for a given kind of box.
 
+NOTE: from css3-regions: "The edges of the first CSS region in a region chain associated with a named flow establish the rectangle that is the containing block used for absolutely positioned elements in the named flow which do not have an ancestor with a ‘position’ of ‘absolute’, ‘relative’ or ‘fixed’ (see [CSS21]). That first CSS region rectangle is used as the containing block instead of the initial containing block. This does not affect fixed position elements in the named flow - they are still positioned relative to the viewport or page area even if they have been redirected to a named flow."
+
 
 =====Anonymous boxes=====
 
@@ -122,6 +124,13 @@ From CSS21:
 From css3-break:
   * "User Agents must apply these ['break-*'] properties to boxes in the normal flow of the fragmentation root. User agents should also apply these properties to floated boxes whose containing block is in the normal flow of the root fragmented element."
 
+Fros css3-regions:
+  * "A named flow is the ordered sequence of elements associated with a flow with a given identifier. Elements in a named flow are ordered according to the document order."
+  * Any element, 'flow-into:<ident>': "The element is taken out of its parent's flow and placed into the flow with the name ‘<ident>’. The element is said to have a specified flow."
+  * "If an element has the same specified flow as one of its ancestors, it becomes a sibling of its ancestor for the purpose of layout in the region chain laying out content from that flow."
+  * 
+
+
 [Note: css3-page 9.4 (Allowed page breaks) says: "In the normal flow, page breaks may occur at the following places".  What does this mean?  Does this indicate that a nested flow root may be fragmented if its its in-flow content has page break opportunities as specified?  Or is it trying to say that page break opportunities only exist in the outermost flow (whatever that actually is)?]
 
 [Note: according to CSS21 9.3, the root element is out of flow.  Is this correct?  Surely it participates in the block formatting context established by the initial containing block.]