define container minimum size using java layouts

i am writing a stand alone app in java using a couple of JPanel with different layouts in order to arrange the user interface. now my problem is that when i take the upper side of the window (its a pannel in a border layout which is inside another panel which using border layout),im tring to add a class that extends panel is order to paint an icon on the top of my window (draw on the panel) . the problem is that the layout is cuting a part of the icon, or in other words, minimazing the panel to a certain size. i tried changing to flowlayout and others but is does the same... so i wanted to ask if an option which tells the layout that a container (panel or others) can not be set to a size lower then a given size exists? other suggestions will allso help but keep in mind that i am tring to add the icon with mininal change to the GUI.

thanks for reading this and helping moshe

Container can hold MinimumSize for JComponent, simple example,

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class CustomComponent extends JFrame {

    private static final long serialVersionUID = 1L;

    public CustomComponent() {
        setTitle("Custom Component Graphics2D");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void display() {
        add(new CustomComponents());//
        pack();
        // enforces the minimum size of both frame and component
        setMinimumSize(getSize());
        setVisible(true);
    }

    public static void main(String[] args) {
        CustomComponent main = new CustomComponent();
        main.display();
    }
}

class CustomComponents extends JPanel {

    private static final long serialVersionUID = 1L;

    @Override
    public Dimension getMinimumSize() {
        return new Dimension(100, 100);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(400, 300);
    }

    @Override
    public void paintComponent(Graphics g) {
        int margin = 10;
        Dimension dim = getSize();
        super.paintComponent(g);
        g.setColor(Color.red);
        g.fillRect(margin, margin, dim.width - margin * 2, dim.height - margin * 2);
    }
}