How to use Groovy SwingBuilder to create a JDesktopPand/JInternalFrame combo?

I am trying to create a Groovy MDI application using SwingBuilder.

I've started with the basic SwingBuilder example at http://groovy-lang.org/swing.html and added calls to desktopPane and internalFrame:

import groovy.swing.SwingBuilder
import java.awt.BorderLayout as BL

count = 0
new SwingBuilder().edt {
  frame(title: 'Frame', size: [300, 300], show: true) {
    desktopPane() {
      internalFrame() {
        borderLayout()
        textlabel = label(text: 'Click the button!', constraints: BL.NORTH)
        button(text:'Click Me',
             actionPerformed: {count++; textlabel.text = "Clicked ${count} time(s)."; println "clicked"}, constraints:BL.SOUTH)
      }
    }
  }
}

However, this code only gets me a blank window.

Looks like I just needed to add visible and bounds parameters to the internalFrame

import groovy.swing.SwingBuilder
import java.awt.BorderLayout as BL

count = 0
new SwingBuilder().edt {
  frame(title: 'Frame', size: [300, 300], show: true) {
    desktopPane() {
      internalFrame(visible: true, bounds: [25, 25, 200, 100]) {
        borderLayout()
        textlabel = label(text: 'Click the button!', constraints: BL.NORTH)
        button(text:'Click Me',
             actionPerformed: {count++; textlabel.text = "Clicked ${count} time(s)."; println "clicked"}, constraints:BL.SOUTH)
      }
    }
  }
}