In merlin, cut/copy/drag are broken for JEditorPane when its EditorKit is an RTFEditorKit. Thus, setting the content-type to "text/rtf" or explicitly setting the EditorKit to an RTFEditorKit will prevent cut/copy/drag from working.

To see the problem, compile and run the following:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;

public class EditorPaneRTFTest extends JFrame {

    JEditorPane ep = new JEditorPane();

    public EditorPaneRTFTest() {
        setTitle("EditorPaneRTFTest");
        setSize(500, 400);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
        setLocation((d.width - getWidth()) / 2, (d.height - getHeight()) / 2);
        
        ep.setContentType("text/rtf");
        try {
            ep.getDocument().insertString(0, "Try copying or moving this.", null);
        } catch (BadLocationException ble) {
        }
        ep.setDragEnabled(true);

        getContentPane().add(new JScrollPane(ep), BorderLayout.CENTER);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                EditorPaneRTFTest test = new EditorPaneRTFTest();
                test.setVisible(true);
            }
        });
    }

}

Try copying the text (CTRL-C) - nothing is copied to the clipboard.
Try cutting the text (CTRL-X) - nothing is put on the clipboard and no text is removed.
Try dragging and dropping the text - the drag and drop completes and no text is transferred.

The expected result is that plain text should be moved/copied around.