laszlokorte/Main.java

## Main.java
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;

import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextArea;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;

public class Main {
	static final Box inner = Box.createVerticalBox();

	// if the jtextarea should contain text
	private static boolean textEnabled = true;

	public static void main(final String[] args) {
		final JFrame frame = new JFrame();

		final JPanel insideScroll = insideScroll();
		final JScrollPane scrollpane = new JScrollPane(insideScroll);
		scrollpane.setAutoscrolls(false);
		scrollpane
		.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
		final JPanel rightPanel = new JPanel();
		rightPanel.setPreferredSize(new Dimension(300, 300));

		rightPanel.addMouseMotionListener(new MouseMotionAdapter() {
			@Override
			public void mouseDragged(final MouseEvent e) {
				super.mouseDragged(e);
				final int pos = scrollpane.getVerticalScrollBar().getValue();
				update();
				SwingUtilities.invokeLater(new Runnable() {

					@Override
					public void run() {
						System.out.println(String.format("[Out] %s", pos));
					}
				});
			}
		});

		// Add labels describing the problem
		rightPanel.setLayout(new BoxLayout(rightPanel, BoxLayout.PAGE_AXIS));
		final JButton toggleButton = new JButton("Toggle text");
		rightPanel.add(toggleButton);
		rightPanel
		.add(new JLabel(
				"<html>If the text is disabled, you can press/drag<br> your mouse on on right side of the<br> window and the scrollbar will<br> stay in its position."));

		rightPanel
		.add(new JLabel(
				"<html>If the text is enabled, the scrollbar<br> will jump around when dragging<br> on the right side."));

		// enable/disable the text when the button is clicked.
		toggleButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(final ActionEvent e) {
				textEnabled = !textEnabled;
				update();
			}
		});

		final JSplitPane split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
				scrollpane, rightPanel);

		frame.add(split);

		// initialize the scrollpane content
		update();

		frame.pack();
		frame.setVisible(true);

		frame.setLocationRelativeTo(null);

	}

	// initializes the components inside the scrollpane
	private static JPanel insideScroll() {
		final JPanel panel = new JPanel();
		panel.setLayout(new BorderLayout());
		panel.add(inner, BorderLayout.NORTH);

		return panel;
	}

	// replaces all components inside the scrollpane
	private static void update() {
		inner.removeAll();

		for (int i = 0; i < 30; i++) {
			inner.add(buildRow(i));
		}

		inner.revalidate();
	}

	// build a single component to be inserted into the scrollpane
	private static JPanel buildRow(final int i) {
		final JPanel row = new JPanel();

		final Color bg = i % 2 == 0 ? Color.DARK_GRAY : Color.LIGHT_GRAY;

		row.setBackground(bg);
		row.setPreferredSize(new Dimension(300, 80));
		row.setLayout(new BorderLayout());

		row.add(textarea(bg), BorderLayout.CENTER);

		return row;
	}

	// build the textarea to be inserted into the cells in the scroll pane
	private static Component textarea(final Color bg) {
		final JTextArea textarea = new JTextArea();

		textarea.setEnabled(false);
		textarea.setLineWrap(true);
		textarea.setBackground(bg);
		textarea.setDisabledTextColor(Color.black);
		textarea.setEditable(false);
		if (textEnabled) {
			textarea.setText("Lorem ipsum dolor si amet. Lorem ipsum dolor si amet. Lorem ipsum dolor si amet");
		}

		return textarea;
	}

}
	import java.awt.BorderLayout;
	import java.awt.Color;
	import java.awt.Component;
	import java.awt.Dimension;
	import java.awt.event.ActionEvent;
	import java.awt.event.ActionListener;
	import java.awt.event.MouseEvent;
	import java.awt.event.MouseMotionAdapter;

	import javax.swing.Box;
	import javax.swing.BoxLayout;
	import javax.swing.JButton;
	import javax.swing.JFrame;
	import javax.swing.JLabel;
	import javax.swing.JPanel;
	import javax.swing.JScrollPane;
	import javax.swing.JSplitPane;
	import javax.swing.JTextArea;
	import javax.swing.ScrollPaneConstants;
	import javax.swing.SwingUtilities;

	public class Main {
	static final Box inner = Box.createVerticalBox();

	// if the jtextarea should contain text
	private static boolean textEnabled = true;

	public static void main(final String[] args) {
	final JFrame frame = new JFrame();

	final JPanel insideScroll = insideScroll();
	final JScrollPane scrollpane = new JScrollPane(insideScroll);
	scrollpane.setAutoscrolls(false);
	scrollpane
	.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
	final JPanel rightPanel = new JPanel();
	rightPanel.setPreferredSize(new Dimension(300, 300));

	rightPanel.addMouseMotionListener(new MouseMotionAdapter() {
	@Override
	public void mouseDragged(final MouseEvent e) {
	super.mouseDragged(e);
	final int pos = scrollpane.getVerticalScrollBar().getValue();
	update();
	SwingUtilities.invokeLater(new Runnable() {

	@Override
	public void run() {
	System.out.println(String.format("[Out] %s", pos));
	}
	});
	}
	});

	// Add labels describing the problem
	rightPanel.setLayout(new BoxLayout(rightPanel, BoxLayout.PAGE_AXIS));
	final JButton toggleButton = new JButton("Toggle text");
	rightPanel.add(toggleButton);
	rightPanel
	.add(new JLabel(
	"<html>If the text is disabled, you can press/drag<br> your mouse on on right side of the<br> window and the scrollbar will<br> stay in its position."));

	rightPanel
	.add(new JLabel(
	"<html>If the text is enabled, the scrollbar<br> will jump around when dragging<br> on the right side."));

	// enable/disable the text when the button is clicked.
	toggleButton.addActionListener(new ActionListener() {
	@Override
	public void actionPerformed(final ActionEvent e) {
	textEnabled = !textEnabled;
	update();
	}
	});

	final JSplitPane split = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
	scrollpane, rightPanel);

	frame.add(split);

	// initialize the scrollpane content
	update();

	frame.pack();
	frame.setVisible(true);

	frame.setLocationRelativeTo(null);

	}

	// initializes the components inside the scrollpane
	private static JPanel insideScroll() {
	final JPanel panel = new JPanel();
	panel.setLayout(new BorderLayout());
	panel.add(inner, BorderLayout.NORTH);

	return panel;
	}

	// replaces all components inside the scrollpane
	private static void update() {
	inner.removeAll();

	for (int i = 0; i < 30; i++) {
	inner.add(buildRow(i));
	}

	inner.revalidate();
	}

	// build a single component to be inserted into the scrollpane
	private static JPanel buildRow(final int i) {
	final JPanel row = new JPanel();

	final Color bg = i % 2 == 0 ? Color.DARK_GRAY : Color.LIGHT_GRAY;

	row.setBackground(bg);
	row.setPreferredSize(new Dimension(300, 80));
	row.setLayout(new BorderLayout());

	row.add(textarea(bg), BorderLayout.CENTER);

	return row;
	}

	// build the textarea to be inserted into the cells in the scroll pane
	private static Component textarea(final Color bg) {
	final JTextArea textarea = new JTextArea();

	textarea.setEnabled(false);
	textarea.setLineWrap(true);
	textarea.setBackground(bg);
	textarea.setDisabledTextColor(Color.black);
	textarea.setEditable(false);
	if (textEnabled) {
	textarea.setText("Lorem ipsum dolor si amet. Lorem ipsum dolor si amet. Lorem ipsum dolor si amet");
	}

	return textarea;
	}

	}