diff --git a/lib/codemirror.js b/lib/codemirror.js
index <HASH>..<HASH> 100644
--- a/lib/codemirror.js
+++ b/lib/codemirror.js
@@ -23,7 +23,7 @@ window.CodeMirror = (function() {
       replaceSelection: operation(replaceSelection),
       focus: function(){window.focus(); focusInput(); onFocus(); fastPoll();},
       setOption: function(option, value) {
-        if (options[option] == value) return;
+        if (options[option] == value && option != "mode") return;
         options[option] = value;
         if (option == "mode" || option == "indentUnit") loadMode();
         else if (option == "readOnly" && value == "nocursor") {onBlur(); input.blur();}
Always force a re-highlight when the 'mode' option is set

Closes #<I>