diff --git a/app/assets/javascripts/app/controllers/ticket_zoom.coffee b/app/assets/javascripts/app/controllers/ticket_zoom.coffee
index 017ca4c4b..8713e705c 100644
--- a/app/assets/javascripts/app/controllers/ticket_zoom.coffee
+++ b/app/assets/javascripts/app/controllers/ticket_zoom.coffee
@@ -8,6 +8,7 @@ class App.TicketZoom extends App.Controller
     'click .js-submit':   'submit'
     'click .js-bookmark': 'bookmark'
     'click .js-reset':    'reset'
+    'click .main':        'muteTask'
 
   constructor: (params) ->
     super
@@ -213,6 +214,9 @@ class App.TicketZoom extends App.Controller
     )
 
 
+  muteTask: =>
+    App.TaskManager.mute(@task_key)
+
   load: (data, force) =>
 
     # remember article ids
@@ -637,9 +641,7 @@ class App.TicketZoom extends App.Controller
           return
 
         @autosaveStart()
-
-        App.TaskManager.mute(@task_key)
-
+        @muteTask()
         @fetch(ticket.id, true)
 
         # enable form
diff --git a/app/assets/javascripts/app/lib/app_post/task_manager.coffee b/app/assets/javascripts/app/lib/app_post/task_manager.coffee
index 0151b8878..c0a77cf73 100644
--- a/app/assets/javascripts/app/lib/app_post/task_manager.coffee
+++ b/app/assets/javascripts/app/lib/app_post/task_manager.coffee
@@ -322,6 +322,7 @@ class _taskManagerSingleton extends App.Controller
     task = @get(key)
     if !task
       throw "No such task with '#{key}' to mute"
+    return if !task.notify
     task.notify = false
     @taskUpdate(task)
 
diff --git a/test/browser/agent_ticket_actions_level2_test.rb b/test/browser/agent_ticket_actions_level2_test.rb
index 5ec2d98c5..0f162aec5 100644
--- a/test/browser/agent_ticket_actions_level2_test.rb
+++ b/test/browser/agent_ticket_actions_level2_test.rb
@@ -244,5 +244,33 @@ class AgentTicketActionsLevel2Test < TestCase
         body: 'some level 2 <b>body</b> in instance 2',
       },
     )
+
+    # modify ticket again and erase modified via mouse click on .active.content
+    ticket_update(
+      browser: browser1,
+      data: {
+        body: 'some update 4711',
+      },
+    )
+    sleep 4
+    verify_task(
+      browser: browser2,
+      data: {
+        title: 'TTTsome level 2 <b>subject<\/b> 123äöü',
+        modified: true,
+      }
+    )
+    click(
+      browser: browser2,
+      css: '.active.content',
+    )
+    sleep 4
+    verify_task(
+      browser: browser2,
+      data: {
+        title: 'TTTsome level 2 <b>subject<\/b> 123äöü',
+        modified: false,
+      }
+    )
   end
 end