'Userform.frm
Option Explicit

Private Sub UserForm_Initialize()
   Dim i%
   For i = 0 To Documents.Count - 1
      ListBox1.AddItem Documents.Item(i).Name
   Next
End Sub

Private Sub ListBox1_Click()
   Dim i%
   With ListBox1
      For i = 0 To .ListCount
         If .Selected(i) Then
            If Documents(i).WindowState = acMin Then Documents(i).WindowState = acNorm
            Documents(i).Activate
            Exit For
         End If
      Next
   End With
End Sub