Prefer jQuery on to bind, and don't use .js class.

app/assets/javascripts/dropzone_input.js.coffee

@@ -15,11 +15,11 @@ class @DropzoneInput
 
     form_textarea = $(form).find("textarea.markdown-area")
     form_textarea.wrap "<div class=\"div-dropzone\"></div>"
-    form_textarea.bind 'paste', (event) =>
+    form_textarea.on 'paste', (event) =>
       handlePaste(event)
-    form_textarea.bind "input", ->
+    form_textarea.on "input", ->
       hideReferencedUsers()
-    form_textarea.bind "blur", ->
+    form_textarea.on "blur", ->
       renderMarkdown()
 
     form_dropzone = $(form).find('.div-dropzone')
@@ -130,11 +130,11 @@ class @DropzoneInput
     child = $(dropzone[0]).children("textarea")
 
     hideReferencedUsers = ->
-      referencedUsers = form.find(".js-referenced-users")
+      referencedUsers = form.find(".referenced-users")
       referencedUsers.hide()
 
     renderReferencedUsers = (users) ->
-      referencedUsers = form.find(".js-referenced-users")
+      referencedUsers = form.find(".referenced-users")
 
       if referencedUsers.length
         if users.length >= 10

app/assets/stylesheets/generic/markdown_area.scss

@@ -60,7 +60,7 @@
   float: left;
 }
 
-.js-referenced-users {
+.referenced-users {
   padding: 10px 0;
   color: #999;
   margin-left: 10px;

app/assets/stylesheets/generic/mobile.scss

@@ -19,7 +19,7 @@
     }
   }
 
-  .js-referenced-users {
+  .referenced-users {
     margin-right: 0;
   }
 

app/views/projects/_md_preview.html.haml

@@ -9,7 +9,7 @@
           Preview
 
     - if defined?(referenced_users) && referenced_users
-      %span.js-referenced-users.pull-left.hide
+      %span.referenced-users.pull-left.hide
         = icon('exclamation-triangle')
         You are about to add
         %strong