Simple Swing app memory grows by resizing the frame

Question

This simple program, and memory (Private Working Set by Task manager) grows by resizing its frame. 32MB (initially) to 140MB and more if I persistently resizing the frame. Why does this happen and is this normal for a Java program ?

import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class TestSwing {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            JFrame frame = new JFrame();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            frame.setVisible(true);
        });
    }
}

I did the same for SWT and JavaFX simple one frame program. Memory growth is very slow as compared to Swing but it seems it grows steadily.

I also did the same for notepad.exe's frame but the memory didn't grow.

I used VisualVM to watch the JVM heap but heap size did not change. So maybe the problem is native memory that GUI library uses.

[ Private Working Set : 31MB (initial) -> 192MB (last) ]

Environment : Windows Vista / Java 8 update 66