Some code before Process.Start isn't executed

Question

As you can see into my code example, when user clicks on Button1, an application starts and program waits until its process name shows up in the processes list.

My "problem" is with the Label1.Text before

Process.Start(@"\application.exe");

Αlthough this.Cursor = Cursors.WaitCursor; works fine, the label doesn't get the updated with the text "Please wait..." while waiting.

What am I doing wrong?

private void Button1_Click(object sender, EventArgs e)
{
    DialogResult result = MessageBox.Show("Do you want to start the application?", "Message", MessageBoxButtons.YesNo, MessageBoxIcon.Question);

    if (result == DialogResult.Yes)
    {
        this.Cursor = Cursors.WaitCursor;
        Label1.Text = "Please wait...";

        Process.Start(@"\application.exe");

        Process[] processes;

        do
        {
            processes = Process.GetProcessesByName("applicationname");
            Thread.Sleep(500);
        }
        while (processes.Length == 0);

        this.Cursor = Cursors.Default;
        Label1.Text = "Done!!!";
    }
}