MDI parent controls are not visible when child form is opened in C#

Question

I have two forms. One is a MDI/parent form and the other is a child form. Parent form has a few controls like label, textbox, button, etc. When I click on a button in the parent form, child form is brought in front of the parent form. But all the controls in the parent form become invisible. I want all the controls in parent form to remain visible when I open the child form. How can I achieve this?

        MdiClient client;
        Form2 myform;
        public Form1()
        {
            InitializeComponent();          

            IsMdiContainer = true;            
            client = Controls.OfType<MdiClient>().First();
            client.GotFocus += (s, e) =>
            {
                if (!MdiChildren.Any(x => x.Visible)) client.SendToBack();
            };    
        }


private void ShowForm(Form childForm)
        {
            client.BringToFront();
            childForm.Show();               
        }

 private void button1_Click(object sender, EventArgs e)
        {
            myform = new Form2() { MdiParent = this };
            ShowForm(myform);
        }