tabFormControl控件内的tabFormPanel要放入Form窗体，但是每次运行项目，窗体在panel内的位置都会改变，怎么样能把窗体位置固定？我给窗体的Location变量赋了位置类定位，无效果。
以下是我的代码：

private void button4_Click(object sender, EventArgs e)
{
        //新建tab项
        TabFormItem tabFormItem2=new TabFormItem();
        TabFormPanel tabFormPanel2 = new TabFormPanel();
        tabFormItem1.Checked = false;
        tabFormItem2.Checked = true;
        tabFormItem2.CloseButtonVisible = true;
        tabFormItem2.ForeColor = System.Drawing.Color.Black;
        tabFormItem2.Name = "tabFormItem2";
        tabFormItem2.Text = "修改密码";
        tabFormItem2.Panel = tabFormPanel2;
        this.tabFormControl1.Items.AddRange(new DevComponents.DotNetBar.BaseItem[] {tabFormItem2});
        
        //新建panel
        tabFormPanel2.Name = "tabFormPanel2";
        tabFormPanel2.Dock = System.Windows.Forms.DockStyle.Fill;
        tabFormPanel2.Location = new System.Drawing.Point(0, 0);
        tabFormPanel2.Style.BackColor = System.Drawing.Color.WhiteSmoke;
        tabFormPanel2.Style.Class = "TabFormPanel";
        tabFormPanel2.Style.CornerType = DevComponents.DotNetBar.eCornerType.Square;
        tabFormPanel2.StyleMouseDown.CornerType = DevComponents.DotNetBar.eCornerType.Square;
        tabFormPanel2.StyleMouseOver.CornerType = DevComponents.DotNetBar.eCornerType.Square;
        
        //新窗体
        Password pass = new Password(u);
        pass.Location = new Point(0, 0);
        pass.Show();
        //设置为非顶级控件
        pass.TopLevel = false;
        tabFormPanel2.Controls.Add(pass);
        tabFormPanel2.Show();
        this.tabFormControl1.Controls.Add(tabFormPanel2);
    }

效果：

而且每次我点击按钮tabFormPanel里的Form都没有显示，切换一下tabFormItem后就能显示了？哪里的问题呢？