Copyright (c) SEMM NL All rights reserved.
Author : Paul Hamaker. Part of JavaLessons.com

This is about javax.swing.JInternalFrame.

We empower it.

Set its position and size. ( x, y, width, height )

Add a button to its contentpane.

And add it to a JDesktopPane's default layer,...

that we created beforehand.

We create and add a second JInternalFrame to the same (default) layer.

We want it on top of the other one ...

with focus.

The desktoppane will be this applet's contentpane.

Don't forget, by default they're invisible.

=========

A JDesktopPane extends JLayeredPane, that offers 5 different layers to add components to, to ensure proper overlapping.

Most components go to the bottommost DEFAULT_LAYER .

On top of this is the PALETTE_LAYER for palettes and floating toolbars .

The MODAL_LAYER is for dialogs that lock up the underlying window, modal dialogs .

The POPUP_LAYER for tooltips and the likes.

The topmost DRAG_LAYER is for temporarily adding a component, when dragging it.

=========

moveToBack and moveToFront are for positioning components relative to others WITHIN the SAME LAYER . A component in the Drag layer will always be painted on top of one in the Default Layer, f.e.

========= Not transparent.

.