[Erel]

This code will prevent the flashing (door is a Door object):

Sub App_Start
    Form1.Show
    door.New1(false)
    door.FromControl("form2")
    door.SetProperty("StartPosition","Manual")
'    door.FromControl("form3")
'    door.SetProperty("StartPosition","Manual")
'    ...
End Sub


Sub Button1_Click
    form2.left = form1.left
    form2.top = form1.top
    form2.Show
End Sub