title: how to report that a panel changed to parent container?
body: <p>I have a panel being changed by an action which swaps out it's child panel with a new panel that has a different minimum Size.  I need to inform my <code>JSplitPane</code> that one of it's children panels has changed so I can call <code>updateToPreferedSize</code> method.  Is there an event that is already fired which I should listen for?  If not, how do I throw an event that the parent can catch to notify it?</p>