How to draw interactive frame over user's desktop using java applet?

I need to capture portion of user screen usign java a开发者_如何学JAVApplet. It is easy to do using Robot class but I'd like user to select which portion of screen to capture in draggy-droppy way.

So I need to draw rectangular frame over users desktop and response when user resizes it.

How could I do it? Thnx.

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Read the section from the Swing tutorial on How to Use Root Panes for an example that shows you how to use a Glass Pane.