Public meineForms() As Boolean

ReDim meineForms(0)
meineForms(0) = False

Dim i As Integer
Dim NeuTitel As Integer
 
NeuTitel = 0
For i = 1 To UBound(meineForms)
    If meineForms(i) = False Then
        NeuTitel = i
        meineForms(i) = True
        Exit For
    End If
Next
If NeuTitel = 0 Then
    NeuTitel = UBound(meineForms) + 1
    ReDim Preserve meineForms(NeuTitel)
    meineForms(NeuTitel) = True
End If
 
Dim F As Form1
Set F = New Form1
F.Caption = "Fenster " & Format(NeuTitel)
F.Tag = NeuTitel
F.Show

meineForms(Me.Tag) = False