1. Set look and feel to GTKLookAndFeel
2. Update JFileChooser component with SwingUtilities.updateComponentTreeUI.

Result: Filter changed to a default toString() output
Expected: Look and feel changed, filter text remains the same
Reproducible: always 

Also reproducible if look and feel is changed when JFileChooser is already shown.
How to reproduce (same file attached):

import java.io.File;
import javax.swing.JFileChooser;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.FileFilter;

/**
 *
 * @author lans
 */

public class FilterTest {
    public static void main(String... args) throws Exception {
        JFileChooser chooser = new JFileChooser();
        chooser.setAcceptAllFileFilterUsed(false);
        chooser.addChoosableFileFilter(new FileFilter() {

            @Override
            public boolean accept(File f) {
                return true;
            }

            @Override
            public String getDescription() {
                return "Whatever";
            }
        });
        javax.swing.UIManager.setLookAndFeel("com.sun.java.swing.plaf.gtk.GTKLookAndFeel");
        SwingUtilities.updateComponentTreeUI(chooser);
        chooser.showOpenDialog(null);
    }
}