Set background color in Java on a JPanel doesn't work

Question

I am working on a \"paint-like\" application (a little drawing software) to familiarize with Java 2D components. Here is my problem: I have a JFrame whose ContentPane is an

Answer 1

This could fix it...

public class Container extends JPanel
{
    public Container() 
    {
        super();
        this.setOpaque(true);
        this.setBackground(Color.WHITE);
    }
}