[css-position-3] Flag open issue

Author: fantasai

css-position-3/Overview.bs

@@ -972,6 +972,9 @@ Auto Margins of Absolutely-Positioned Boxes</h3>
 	the space distributed to ''margin/auto'' [=margins=]
 	can be negative in [=absolute positioning=].
 
+	ISSUE(11478): What should happen in “negatively-sized” containing blocks?
+	CSS2.1 and this draft currently conflict.
+
 <h2 id=abspos-alignment>
 Self-Alignment of Absolutely Positioned Boxes</h2>