JButton Size doesnt work GridLayout

Hello, i tried to create a GridLayout with 2TextAreas and 1 Button but the button always fills out the whole field even
with setPreferredSize
why is that so?

JPanel erklärung = new JPanel(new GridLayout(1,3));
                      
                     JFrame fenster = new JFrame("Geschwindigkeit");
                     
                     JTextArea textArea = new JTextArea();

                     fenster.add(erklärung);
                     textArea.setEditable(false);
                     textArea3.setEditable(true);
                     textArea.setBackground(Color.ORANGE);
                     textArea3.setBackground(Color.WHITE);
                     textArea.setFont(new Font("Times New Roman",1,22)); //Größe einstellen
                     textArea.append(" Geschwindigkeit festlegen");
                     textArea3.append("");
                     JButton eingabe = new JButton ("Eingabe");
                     eingabe.setPreferredSize(new Dimension(100,25));
                     erklärung.add(textArea);
                     erklärung.add(textArea3);
                     erklärung.add(eingabe);
                     fenster.setSize(400, 100);
                     fenster.setLocation(320, 500);
                     fenster.setVisible(true);
                     fenster.add(eingabe);
                     fenster.setResizable(true);
                     fenster.pack();