[Stage] Setting 'icons' to null do not reset the Stage icon

This is reproducible with marina b05. Setting 'icons' to null do not reset the Stage icon.

To reproduce, run the below test. It shows a Stage with a duke image set as Stage icon. On clicking a button on stage, the icons is set to null. This doesn't reset the Stage icon.

import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.image.*;
import javafx.scene.control.*;

var icons: Image[] = [Image {
    url: "http://sqindia.india.sun.com/disk11/jfc/mercurial_workspaces/FX_Test_WS/resources/images/duke.png"
}, Image {
    url: "http://sqindia.india.sun.com/disk11/jfc/mercurial_workspaces/FX_Test_WS/resources/images/duke.jpg"
}];
Stage {
    width: 200
    height: 200
    icons: bind icons
    scene: Scene {
        content: Button {
            text: "Null Icons"
            action: function() {
                //delete icons;
                icons = null;
            }
        }
    }
}