To do this, add an attribute to the window called debug and give it a value of true . This will cause the window to display the boxes and springs so you can see what is happening. The example below shows how to use it. The image below shows the effect when applied to the find files dialog. Rectangles have been drawn around all of the boxes.
Blue boxes indicate horizontal boxes.
You can see that the entire window is also a horizontal box. Red boxes indicate vertical boxes. Zigzags show where there are flexible elements. In this case, the spring is flexible so a zigzag appears above it. Lines show where inflexible elements are, in this case the text, the input field and the buttons.