WebCharts3D component fires a selection change event when an end-user clicks on one of the chart's active elements. To process a selection change event, add an instance of MxComponentListener to the chart and check the event id for MxComponentEvent.STATE_CHANGED, for example:

	chart.addMxComponentListener(
		new MxComponentListener() { 
			public void componentChanged(MxComponentEvent event) { 
				if(event.getID() == MxComponentEvent.STATE_CHANGED) { 
				 	// some action code here 
				 } 
			} 
		});

You can see this example running by selecting Samples topic of Swing section in WebCharts3D Designer's Help and clicking the appropriate sample link.