Allow user to select any installed LaF

[FliegendeWurst]

This is another style available by default.

EDIT: Code has been adapted as suggested by @wadoon.

[wadoon]

Should we not try to find the LaF automatically?

Oracle gives this snippet

import javax.swing.UIManager.*;

try {
    for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
        if ("Nimbus".equals(info.getName())) {
            UIManager.setLookAndFeel(info.getClassName());
            break;
        }
    }
} catch (Exception e) {
    // If Nimbus is not available, you can set the GUI to another look and feel.
}

It should simple to fill out the array from LookAndFeelInfos.