/// <summary>
 /// Handles the Init event of the Page control.
 /// </summary>
 /// <param name="sender">The source of the event.</param>
 /// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
 protected void Page_Init(object sender, EventArgs e)
 {
     if (!Visible)
     {
         return;
     }
     if (ContextService.HasContext("AddFilterStateInfo"))
     {
         _State = ContextService.GetContext("AddFilterStateInfo") as AddFilterStateInfo;
     }
     if (_State == null)
     {
         _State = new AddFilterStateInfo {
             EntityID = EntityContext.EntityID.ToString()
         };
         AddDistinctGroupItemsToList();
         AddDistinctStageItemsToList();
     }
     PopulateListBoxControl(lbxPriority, "Lead Priority");
     PopulateListBoxControl(lbxStatus, "Target Status");
     lbxGroups.SelectedIndex   = _State.groupFilter;
     lbxPriority.SelectedIndex = _State.priorityFilter;
     lbxStages.SelectedIndex   = _State.stageFilter;
     lbxStatus.SelectedIndex   = _State.statusFilter;
 }