Only show overview edit options as admin.

app/assets/javascripts/app/controllers/ticket_overview.coffee

@@ -250,6 +250,8 @@ class Table extends App.Controller
 
     # render init page
     checkbox = true
+    edit     = false
+    if @isRole('Admin')
       edit = true
     if @isRole('Customer')
       checkbox = false
@@ -271,7 +273,6 @@ class Table extends App.Controller
     html = App.view('agent_ticket_view/content')(
       overview:   @overview
       view_modes: view_modes
-      checkbox:   checkbox
       edit:       edit
     )
     html = $(html)