无法在Powershell GUI中显示分组框

Add-Type -AssemblyName System.Windows.Forms

$form = New-Object System.Windows.Forms.Form
$form.Size = New-Object System.Drawing.Size(400, 300)

$label = New-Object System.Windows.Forms.Label
$label.Text = "分组框标题"
$label.BackColor = [System.Drawing.Color]::LightGray
$label.AutoSize = $true
$label.Location = New-Object System.Drawing.Point(10, 10)

$textBox = New-Object System.Windows.Forms.TextBox
$textBox.Location = New-Object System.Drawing.Point(20, 40)
$textBox.Size = New-Object System.Drawing.Size(200, 20)

$form.Controls.Add($label)
$form.Controls.Add($textBox)

$form.ShowDialog()