C# xtraTabControl 添加from窗体，在tabPage中动态添加的窗体,无法随tabpage动态调整大小

 //ctl.WindowState = FormWindowState.Maximized; 此行代码必须注释掉，否则窗体内的控件不会随父窗体大小变化，而调整
                ctl.Name = tabName + flag.ToString();
                ctl.Text = tabText;
                ctl.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None; //设置窗体为非边框样式           
                ctl.Dock = System.Windows.Forms.DockStyle.Fill; //设置样式是否填充整个panel               
                ctl.Tag = flag; 
                //-------------------------------------
                XtraTabPage tb = new XtraTabPage();
                tb.Name = "tab_" + tabName + flag.ToString();
                tb.Text = tabText;
                tb.Dock = System.Windows.Forms.DockStyle.Fill; //设置样式是否填充整个panel                    
                //--------------------------------------------------------               
                xtraTabControl1.TabPages.Add(tb);
                xtraTabControl1.SelectedTabPage = tb;//显示该页
                //-------------------------------------------                   
                ctl.TopLevel = false;      //设置为非顶级窗体  
                tb.Controls.Add(ctl); //页面添加 容器
                ctl.Show();