Showing MDI Child - A random form visible only for a millisecond appearing on the screen

Question

I have an MDI form with treeview on the left and form to appear on the right with splitter towards left side. I want to open a form based on the user click on the node within treeview how do I do it properly. The problem is that when I open new form a random one pops up on the screen for a milisecond and then it disappears, and the one that mean to appear is showing straight after. Here is my code so far:

private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
    CloseAllMdiChildForms();
    if (e.Node.Name == "root")
    {
        CustomerFrm cf = new CustomerFrm();
        cf.Show();
        cf.MdiParent = this;
    }

    //treeView1.MouseClick();
    //if (treeView1.SelectedNode.Level == 0)
    //{
    //    CustomerFrm CF = new CustomerFrm();
    //    CF.ShowDialog();
    //}
} 

There is a random form visible only for a millisecond appearing on the screen without reason. What's the problem?

Answer 1

The flicker is because you first show the form and then set its MdiParent. So it flickers; it shows outside the mdi area and then after setting its MdiParent it shows in mdi client area.

To solve the problem, it's enough to first set cf.MdiParent = this; and then call cf.Show();.