Aca ta el code:
Código
Private Sub mnuGuardar_Click() On Error GoTo errSub If Forms.Count = 1 Then MsgBox "No hay documentos para guardar", vbInformation Exit Sub End If If InStr(1, ActiveForm.Caption, sCaption) Then CommonDialog1.ShowSave If CommonDialog1.FileName = "" Then Exit Sub ActiveForm.RichTextBox1.SaveFile CommonDialog1.FileName Else ActiveForm.RichTextBox1.SaveFile ActiveForm.Caption End If Exit Sub errSub: Select Case Err.Number Case 91 Resume Next End Select
Fuente: http://www.recursosvisualbasic.com.ar/htm/tutoriales/visual-basic-mdi.htm
La duda es sencilla pero pes no la he podido resolver...
Saludos...