Run two instances of the code below.
Select a color in the first color chooser.
Drag and drop the selected color from the first color chooser
preview panel to the second color chooser preview panel.

The color is not dragged.

-----------
import javax.swing.BorderFactory;
import javax.swing.JColorChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class JColorChooserDnDTest {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                JPanel panel = new JPanel();
                JColorChooser colorChooser = new JColorChooser();
                colorChooser.setDragEnabled(true);
                panel.setBorder(BorderFactory.createTitledBorder("JColorChoosers"));
                panel.add(colorChooser);
                frame.setContentPane(panel);
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
}
-----------