diff --git a/lib/ace/placeholder.js b/lib/ace/placeholder.js
index 11eaf767..2b9ec30d 100644
--- a/lib/ace/placeholder.js
+++ b/lib/ace/placeholder.js
@@ -45,8 +45,8 @@ var PlaceHolder = function(session, length, pos, others, mainClass, othersClass)
     this.length = length;
     this.session = session;
     this.doc = session.getDocument();
-    this.mainClass = mainClass || "ace_placeholder_main";
-    this.othersClass = othersClass || "ace_placeholder";
+    this.mainClass = mainClass;
+    this.othersClass = othersClass;
     this.$onUpdate = this.onUpdate.bind(this);
     this.doc.on("change", this.$onUpdate);
     this.$others = others;