If you set the forms visible property to false and then true again the Evo2 control never reappears.
If you create a simple MDI application, add a form with a button and Evo2 on it, the following click handler demonstrates the problem.
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click Me.Visible = False Application.DoEvents() System.Threading.Thread.Sleep(5000) Me.Visible = True End Sub