why my user control load event raise again when it's parent is closing

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C#

Hi,I use a user control in a tab document. the problem is when I close tab, user control load event, will raise.
I used this code to add my user control to rad dock(telerik tab document component)
when I try to close "DWTimeCard ","UC_3TimeCard" load event will raise!!!

private void CreateTimeCardTab(UC_3TimeCard Frm)
       {
           DocumentWindow DWTimeCard = new DocumentWindow();
           DWTimeCard.Text = "";
           DWTimeCard.Name = "DWTimeCard";
           DWTimeCard.CloseAction = DockWindowCloseAction.CloseAndDispose;
           DWTimeCard.Disposed += new EventHandler(DWTimeCard_Disposed);
           Frm.DataAvailable+=new EventHandler(ListShow_DataAvailable);
           this.radDock1.AddDocument(DWTimeCard);
           this.radDock1.ActiveWindow = DWTimeCard;
           DWTimeCard.Controls.Add(Frm);
           Frm.Dock = DockStyle.Fill;
           Flag_DWTimeCard = true;
           Frm.Show();
       }
       void DWTimeCard_Disposed(object sender, EventArgs e)
       {
           Flag_DWTimeCard = false;
       }