[ttml1] add note about use of non-applicable style attributes (8.2) (issue 167)
--- a/ttml1/spec/ttml1-changes.html Sat Aug 24 18:56:24 2013 -0600
+++ b/ttml1/spec/ttml1-changes.html Sun Aug 25 09:37:52 2013 -0600
@@ -63,6 +63,8 @@
(this support was removed in the sytnax definition and schema before REC was published,
but this sentence was inadvertently left in the text).
+* In 8.2, add note about the use of non-applicable style attributes.
+
* In 8.2.7, correct typo where "initial" value was written, but "computed" value
intended.
--- a/ttml1/spec/ttml1.xml Sat Aug 24 18:56:24 2013 -0600
+++ b/ttml1/spec/ttml1.xml Sun Aug 25 09:37:52 2013 -0600
@@ -3451,6 +3451,14 @@
style property on ancestor elements to which the property
does not apply.</p>
</note>
+<note role="usage">
+<p>Due to the general syntax of this specification (and the schemas it references) with respect
+to how style attributes are specified, particularly for the purpose of supporting inheritance,
+it is possible for an author to inadvertently specify a non-inheritable style attribute on
+an element that applies neither to that element or any of its descendants while still remaining
+conformant from a content validity perspective. Content authors may wish to make use of TTML
+content verification tools that detect and warn about such usage.</p>
+</note>
<div3 id="style-attribute-style">
<head>style</head>
<p>The <att>style</att> attribute is used by referential style association