title: show label when user mouseOver ValueMarker in jFreeChart
body: <p>Right now i a JFreeChart line graph. I want to add marker to mark some events. I have added the markers. The problem is that the marker labels have started to overlap. I want to solve this by only showing the marker label if the user mouse over's the marker line. How can i capture the mouseover event?</p>
  
  <pre><code>Marker tempMarker = new ValueMarker(hour.getFirstMillisecond());        
  tempMarker.setPaint(Color.BLACK); 
  tempMarker.setLabelAnchor(RectangleAnchor.TOP_LEFT);
  tempMarker.setLabelTextAnchor(TextAnchor.TOP_RIGHT);
  
  //instead of this i want a mouseoverlistner and then show the label
  tempMarker.setLabel("Event Name");
  </code></pre>
  
  <hr>
  
  <p>code for mouse over</p>
  
  <pre><code>chartPanel.addChartMouseListener(new ChartMouseListener() {
      @Override
      public void chartMouseClicked(ChartMouseEvent event) {
          //do something on mouse click
      }
  
      @Override
      public void chartMouseMoved(ChartMouseEvent event) {
          System.out.println("Entity Type: " + event.getEntity());
      }
  });
  </code></pre>
  
  <p>When i mouse over the Marker objects a ChartEntity is sent to the chartMouseMoved. This is the same as when i mouse over other non filled portions of the chart.</p>