How to make "Open File..." window in netbeans PLATFORM?

I need to create something li开发者_开发问答ke internal frame in netbeans platform, which loads file from any location. I tried it by jInternalFrame, but I was not able to find some container to which I can add my frame. I am working in netbeans platform, which has own pre-created main window.

Pease help me by any advice, I am dealing with this about 10 hours, still without result.

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Use WindowManager.getDefault().getMainWindow() as parent for JFileChooser dialog.