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[Helmi]

Hallo,
probiers mal so:

Code:

procedure TForm1.Button1Click(Sender: TObject); 
begin 
  If Assigned(Form3) then         //ich vermute du meinst Form3
    If Form3.Visible = true then 
      Application.CreateForm(TForm2, Form2); 
end; 

procedure TForm1.Button2Click(Sender: TObject); 
begin 
Application.CreateForm(TForm3, Form3); 
end;

mfg
Helmi