[css-break] Clarify parallel fragmentation

Author: fantasai

css-break/Overview.html

@@ -401,8 +401,13 @@ <h2 id=fragmentation-model><span class=secno>2. </span> Fragmentation Model
    remaining content to be laid out in the next <a
    href="#fragmentainer"><i>fragmentainer</i></a>, in some cases causing a
    new <a href="#fragmentainer"><i>fragmentainer</i></a> to be generated to
-   hold the deferred content. When multiple flows are laid out in parallel,
-   fragmentation is performed independently in each flow.
+   hold the deferred content.
+
+  <p> When multiple flows are laid out in parallel, fragmentation is
+   performed independently in each flow. For example, if an element is
+   floated, then a forced break inside the float will not affect the content
+   wrapping outside the float (except insofar as it may increase the height
+   of the float).
 
   <p> Breaking a <a href="#fragmentainer"><i>fragmentainer</i></a>
    <var>F</var> effectively splits the <a

css-break/Overview.src.html

@@ -175,8 +175,15 @@ <h2 id="fragmentation-model">
     and causes the remaining content to be laid out in the next <i>fragmentainer</i>,
     in some cases causing a new <i>fragmentainer</i> to be generated
     to hold the deferred content.
+  </p>
+
+  <p>
     When multiple flows are laid out in parallel,
     fragmentation is performed independently in each flow.
+    For example, if an element is floated,
+    then a forced break inside the float
+    will not affect the content wrapping outside the float
+    (except insofar as it may increase the height of the float).
   </p>
 
   <p>