public function Sink($DiscussionID = '', $Sink = TRUE, $From = 'list') {
      // Make sure we are posting back.
      if (!$this->Request->IsPostBack())
         throw PermissionException('Javascript');
      
      $Discussion = $this->DiscussionModel->GetID($DiscussionID);
      
      if (!$Discussion)
         throw NotFoundException('Discussion');
      
      $this->Permission('Vanilla.Discussions.Sink', TRUE, 'Category', $Discussion->PermissionCategoryID);
      
      // Sink the discussion.
      $this->DiscussionModel->SetField($DiscussionID, 'Sink', $Sink);
      $Discussion->Sink = $Sink;
      
      // Redirect to the front page
      if ($this->_DeliveryType === DELIVERY_TYPE_ALL) {
         $Target = GetIncomingValue('Target', 'discussions');
         Redirect($Target);
      }
      
      $this->SendOptions($Discussion);
      
      $this->JsonTarget("#Discussion_$DiscussionID", NULL, 'Highlight');
      $this->JsonTarget(".Discussion #Item_0", NULL, 'Highlight');
      
      $this->Render('Blank', 'Utility', 'Dashboard');
   }