Refix copy/paste of XHTML to treat it like it does XML -- as plaintext-only

content, since we can't actually copy/paste XML usefully.  Bug 270145, r+sr=jst

content/base/src/nsCopySupport.cpp

@@ -319,9 +319,13 @@ nsresult nsCopySupport::IsPlainTextContext(nsISelection *aSel, nsIDocument *aDoc
     }
   }
   
-  // also consider ourselves in a text widget if we can't find an html document
+  // also consider ourselves in a text widget if we can't find an html
+  // document. Note that XHTML is not counted as HTML here, because we can't
+  // copy it properly (all the copy code for non-plaintext assumes using HTML
+  // serializers and parsers is OK, and those mess up XHTML).
   nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(aDoc);
-  if (!htmlDoc) *aIsPlainTextContext = PR_TRUE;
+  if (!htmlDoc || aDoc->IsCaseSensitive())
+    *aIsPlainTextContext = PR_TRUE;
 
   return NS_OK;
 }

content/base/src/nsDocumentEncoder.cpp

@@ -301,6 +301,7 @@ nsDocumentEncoder::SerializeNodeStart(nsIDOMNode* aNode, PRInt32 aStartOffset,
     }
     case nsIDOMNode::CDATA_SECTION_NODE:
     {
+      NS_ERROR("aaa");
       nsCOMPtr<nsIDOMCDATASection> cdata = do_QueryInterface(node);
       mSerializer->AppendCDATASection(cdata, aStartOffset, aEndOffset, aStr);
       break;
@@ -1144,7 +1145,8 @@ nsHTMLCopyEncoder::SetSelection(nsISelection* aSelection)
   
   // also consider ourselves in a text widget if we can't find an html document
   nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(mDocument);
-  if (!htmlDoc) mIsTextWidget = PR_TRUE;
+  if (!htmlDoc || mDocument->IsCaseSensitive())
+    mIsTextWidget = PR_TRUE;
   
   // normalize selection if we are not in a widget
   if (mIsTextWidget)