Try to catch race condition of opening tasks twice.

app/assets/javascripts/app/controllers/navigation.js.coffee

@@ -131,6 +131,8 @@ class App.Navigation extends App.ControllerWidgetPermanent
       user: user
     )
 
+    @taskbar = new App.TaskbarWidget( el: @$('.tasks') )
+
     # renderMenu
     @renderMenu()
 
@@ -274,8 +276,6 @@ class App.Navigation extends App.ControllerWidgetPermanent
       el: @el
     )
 
-    @taskbar = new App.TaskbarWidget( el: @$('.tasks') )
-
   getItems: (data) ->
     navbar =  _.values(data.navbar)
 

app/assets/javascripts/app/lib/app_post/task_manager.js.coffee

@@ -132,6 +132,11 @@ class _taskManagerSingleton extends Spine.Module
     # input validation
     params.key = App.Utils.htmlAttributeCleanup(params.key)
 
+    # in case an init execute arrives later but is aleady executed, ignore it
+    if params.init && @tasksStarted[params.key]
+      #console.log('IGNORE LATER INIT', params)
+      return
+
     # remember started task / prevent to open task twice
     createNewTask = true
     if @tasksStarted[params.key]
@@ -142,11 +147,6 @@ class _taskManagerSingleton extends Spine.Module
     if params.init
       params.params.init = true
 
-    # in case an init execute arrives later but is aleady executed, ignore it
-    if params.init && @workers[ params.key ]
-      #console.log('IGNORE LATER INIT', params)
-      return
-
     # remember latest active controller
     if params.show
       @activeTaskHistory.push _.clone(params)