Win.CodeNavi.frmMain.frmMain_MdiChildActivate C# (CSharp) Method

        private void frmMain_MdiChildActivate(object sender, EventArgs e)
        {
            //this.SuspendLayout();
            //DrawingControl.SuspendUpdate.Suspend(this);

            // If child form is new and no has tabPage,
            // create new tabPage
            if (this.MdiChildren.Count() > 0)
            {
                if (this.ActiveMdiChild != null && this.ActiveMdiChild.Tag == null)
                {
                    // Add a tabPage to tabControl with child
                    // form caption
                    TabPage tp = new TabPage(this.ActiveMdiChild.Text);
                    tp.Tag = this.ActiveMdiChild;
                    tp.ToolTipText = this.ActiveMdiChild.Text;
                    tp.Parent = tabForms;
                    tabForms.SelectedTab = tp;
                    this.ActiveMdiChild.Tag = tp;
                    this.ActiveMdiChild.FormClosed += new FormClosedEventHandler(ActiveMdiChild_FormClosed);
                    //this.ActiveMdiChild.SizeChanged += new EventHandler(ActiveMdiChild_SizeChanged);
                }
                else
                {
                    tabForms.SelectedTab = this.ActiveMdiChild.Tag as TabPage;
                }
                tabStack.Add(tabForms.SelectedTab);
            }
            else
            {
                tabForms.TabPages.Clear();
            }
            //this.ResumeLayout();
            //DrawingControl.SuspendUpdate.Resume(this);
            if (this.ActiveMdiChild != null ) this.ActiveMdiChild.Refresh();
            else tabForms.TabPages.Clear();
            //SourceCodeMarkUp.SendMessage(this.Handle, SourceCodeMarkUp.WM_NCPAINT, 0, IntPtr.Zero);
            tabForms.Update();
        }