diff --git a/lib/ace/mode/xml_util.js b/lib/ace/mode/xml_util.js
index 63e6b1b7..b58df44f 100644
--- a/lib/ace/mode/xml_util.js
+++ b/lib/ace/mode/xml_util.js
@@ -112,7 +112,7 @@ exports.tag = function(states, name, nextState) {
             }
         },        
         merge : true,
-        regex : "[-_a-zA-Z0-9:!]+",
+        regex : "[-_a-zA-Z0-9:]+",
         next : name + "_embed_attribute_list" 
     }, {
         token: "empty",