CodeMirror.defineMode("xml", function(config, parserConfig) {
  var indentUnit = config.indentUnit;
  var Kludges = parserConfig.htmlMode ? {
    autoSelfClosers: {"br": true, "img": true, "hr": true, "link": true, "input": true,
                      "meta": true, "col": true, "frame": true, "base": true, "area": true},
    doNotIndent: {"pre": true, "!cdata": true},
    allowUnquoted: true
  } : {autoSelfClosers: {}, doNotIndent: {"!cdata": true}, allowUnquoted: false};
  var alignCDATA = parserConfig.alignCDATA;

  // Return variables for tokenizers
  var tagName, type;

  function inText(stream, state) {
    function chain(parser) {
      state.tokenize = parser;
      return parser(stream, state);
    }

    var ch = stream.next();
    if (ch == "<") {
      if (stream.eat("!")) {
        if (stream.eat("[")) {
          if (stream.match("CDATA[")) return chain(inBlock("atom", "]]>"));
          else return null;
        }
        else if (stream.match("--")) return chain(inBlock("comment", "-->"));
        else if (stream.match("DOCTYPE", true, true)) {
          stream.eatWhile(/[\w\._\-]/);
          return chain(inBlock("meta", ">"));
        }
        else return null;
      }
      else if (stream.eat("?")) {
        stream.eatWhile(/[\w\._\-]/);
        state.tokenize = inBlock("meta", "?>");
        return "meta";
      }
      else {
        type = stream.eat("/") ? "closeTag" : "openTag";
        stream.eatSpace();
        tagName = "";
        var c;
        while ((c = stream.eat(/[^\s\u00a0=<>\"\'\/?]/))) tagName += c;
        state.tokenize = inTag;
        return "tag";
      }
    }
    else if (ch == "&") {
      stream.eatWhile(/[^;]/);
      stream.eat(";");
      return "atom";
    }
    else {
      stream.eatWhile(/[^&<]/);
      return null;
    }
  }

  function inTag(stream, state) {
    var ch = stream.next();
    if (ch == ">" || (ch == "/" && stream.eat(">"))) {
      state.tokenize = inText;
      type = ch == ">" ? "endTag" : "selfcloseTag";
      return "tag";
    }
    else if (ch == "=") {
      type = "equals";
      return null;
    }
    else if (/[\'\"]/.test(ch)) {
      state.tokenize = inAttribute(ch);
      return state.tokenize(stream, state);
    }
    else {
      stream.eatWhile(/[^\s\u00a0=<>\"\'\/?]/);
      return "word";
    }
  }

  function inAttribute(quote) {
    return function(stream, state) {
      while (!stream.eol()) {
        if (stream.next() == quote) {
          state.tokenize = inTag;
          break;
        }
      }
      return "string";
    };
  }

  function inBlock(style, terminator) {
    return function(stream, state) {
      while (!stream.eol()) {
        if (stream.match(terminator)) {
          state.tokenize = inText;
          break;
        }
        stream.next();
      }
      return style;
    };
  }

  var curState, setStyle;
  function pass() {
    for (var i = arguments.length - 1; i >= 0; i--) curState.cc.push(arguments[i]);
  }
  function cont() {
    pass.apply(null, arguments);
    return true;
  }

  function pushContext(tagName, startOfLine) {
    var noIndent = Kludges.doNotIndent.hasOwnProperty(tagName) || (curState.context && curState.context.noIndent);
    curState.context = {
      prev: curState.context,
      tagName: tagName,
      indent: curState.indented,
      startOfLine: startOfLine,
      noIndent: noIndent
    };
  }
  function popContext() {
    if (curState.context) curState.context = curState.context.prev;
  }

  function element(type) {
    if (type == "openTag") {curState.tagName = tagName; return cont(attributes, endtag(curState.startOfLine));}
    else if (type == "closeTag") {
      var err = false;
      if (curState.context) {
        err = curState.context.tagName != tagName;
      } else {
        err = true;
      }
      if (err) setStyle = "error";
      return cont(endclosetag(err));
    }
    else if (type == "string") {
      if (!curState.context || curState.context.name != "!cdata") pushContext("!cdata");
      if (curState.tokenize == inText) popContext();
      return cont();
    }
    else return cont();
  }
  function endtag(startOfLine) {
    return function(type) {
      if (type == "selfcloseTag" ||
          (type == "endTag" && Kludges.autoSelfClosers.hasOwnProperty(curState.tagName.toLowerCase())))
        return cont();
      if (type == "endTag") {pushContext(curState.tagName, startOfLine); return cont();}
      return cont();
    };
  }
  function endclosetag(err) {
    return function(type) {
      if (err) setStyle = "error";
      if (type == "endTag") { popContext(); return cont(); }
      setStyle = "error";
      return cont(arguments.callee);
    }
  }

  function attributes(type) {
    if (type == "word") {setStyle = "attribute"; return cont(attributes);}
    if (type == "equals") return cont(attvalue, attributes);
    if (type == "string") {setStyle = "error"; return cont(attributes);}
    return pass();
  }
  function attvalue(type) {
    if (type == "word" && Kludges.allowUnquoted) {setStyle = "string"; return cont();}
    if (type == "string") return cont(attvaluemaybe);
    return pass();
  }
  function attvaluemaybe(type) {
    if (type == "string") return cont(attvaluemaybe);
    else return pass();
  }

  return {
    startState: function() {
      return {tokenize: inText, cc: [], indented: 0, startOfLine: true, tagName: null, context: null};
    },

    token: function(stream, state) {
      if (stream.sol()) {
        state.startOfLine = true;
        state.indented = stream.indentation();
      }
      if (stream.eatSpace()) return null;

      setStyle = type = tagName = null;
      var style = state.tokenize(stream, state);
      state.type = type;
      if ((style || type) && style != "comment") {
        curState = state;
        while (true) {
          var comb = state.cc.pop() || element;
          if (comb(type || style)) break;
        }
      }
      state.startOfLine = false;
      return setStyle || style;
    },

    indent: function(state, textAfter) {
      var context = state.context;
      if (context && context.noIndent) return 0;
      if (alignCDATA && /<!\[CDATA\[/.test(textAfter)) return 0;
      if (context && /^<\//.test(textAfter))
        context = context.prev;
      while (context && !context.startOfLine)
        context = context.prev;
      if (context) return context.indent + indentUnit;
      else return 0;
    },

    compareStates: function(a, b) {
      if (a.indented != b.indented) return false;
      for (var ca = a.context, cb = b.context; ; ca = ca.prev, cb = cb.prev) {
        if (!ca || !cb) return ca == cb;
        if (ca.tagName != cb.tagName) return false;
      }
    },

    electricChars: "/"
  };
});

CodeMirror.defineMIME("application/xml", "xml");
CodeMirror.defineMIME("text/html", {name: "xml", htmlMode: true});

@@ -6494,16 +6494,44 @@
 indented
+ %7C%7C a.tokenize != b.tokenize
 ) return

Make compareStates in XML mode more reliable