Dim F As Form
 
For Each F In Forms
  Debug.Print F.Name
Next

Private Declare Function GetActiveWindow Lib "user32" () As Long

  Dim hWnd As Long
  Dim F As Form
 
  hWnd = GetActiveWindow()
  For Each F In Forms
    If F.hWnd = hWnd Then
      MsgBox F.Name & " ist gerade aktiv!"
    End If
  Next