Use instance property to enable/disable label assignment

app/assets/javascripts/issuable.js.coffee

@@ -91,6 +91,6 @@ issuable_created = false
       $('#update_issues_ids').val []
       $('.issues_bulk_update').hide()
       $('.issues-other-filters').show()
-      @issuableBulkActions.disableWillUpdate()
+      @issuableBulkActions.willUpdateLabels = false
     return true

app/assets/javascripts/issues-bulk-assignment.js.coffee

@@ -10,22 +10,13 @@ class @IssuableBulkActions
     # Save instance
     @form.data 'bulkActions', @
-    @disableWillUpdate()
+    @willUpdateLabels = false
     @bindEvents()
     # Fixes bulk-assign not working when navigating through pages
     Issuable.initChecks();
-  enableWillUpdate: ->
-    @toggleWillUpdate(true)
-
-  disableWillUpdate: ->
-    @toggleWillUpdate(false)
-
-  toggleWillUpdate: (enable)->
-    @willUpdateLabels = if enable? then enable else not @willUpdateLabels
-
   getElement: (selector) ->
     @container.find selector

app/assets/javascripts/labels_select.js.coffee

@@ -383,4 +383,4 @@ class @LabelsSelect
   enableBulkLabelDropdown: ->
     if $('.selected_issue:checked').length
       issuableBulkActions = $('.bulk-update').data('bulkActions')
-      issuableBulkActions.enableWillUpdate()
+      issuableBulkActions.willUpdateLabels = true