GTAScripthookMenuSample

Private mainForm As GTA.Forms.Form
    Private particleLists As GTA.Forms.Listbox
...
mainForm = New GTA.Forms.Form
        mainForm.Text = "PTFX demo"
        mainForm.StartPosition = GTA.FormStartPosition.CenterScreen

        particleLists = New GTA.Forms.Listbox()
        particleLists.Parent = mainForm
        particleLists.Location = New Drawing.Point(15, 15)
        particleLists.Width = 300
        particleLists.Height = mainForm.Height - 55
...
mainForm.Show()
...
mainForm.Close()