The attached program creates a Group that is a 60 x 60 array of Rectangles. The Rectangles are 10 x 10, and are 5 apart with a margin of 5 on top, bottom, left, and right.

The layoutBounds of the Group are
    minX = 5, minY = 5, maxX =900, maxY = 900

Regarding onMousePressed (et. al.), the doc says
     Defines a function to be called when a mouse button is pressed on this Node.

The question is, what does 'on this Node' mean?
- On the one hand, that could mean if a button is pressed within the above bounds. In this case, onMousePressed should be called
  if a button is pressed anywhere in the above bounds.

- On the other hand, the Group doc also says
      A Group will take on the collective bounds of its children
  which sounds like it means that the bounds of a group is actually a sequence of the bounds of its children.
  This could mean that onMousePressed is only called if the location is inside the bounds of a child.

The latter is what happens. I think the doc should be clarified.