[closed] how to set the right tooltiptext for the graph?

hi,i use the following code to set the tooltiptext for a graph(JGraph)!But it does not work the right way!When my cursor is above the cell,it does not display the tooltiptext,however when it leaves the cell,the tooltiptext appears!What i want is that when my cursor is above a cell,it displays the tooltiptext immediately .

sorry for my english :)\nthanks!

here is the code:

GraphModel model = new DefaultGraphModel();

   GraphLayoutCache view = new GraphLayoutCache(model,new DefaultCellViewFactory());\n\n   final JGraph graph = new JGraph(model,view);\n\n   DefaultGraphCell dgc=new DefaultGraphCell("Hello");\n   GraphConstants.setBounds(dgc.getAttributes(),new Rectangle2D.Double(20,20,40,20));\n\n   GraphConstants.setGradientColor(dgc.getAttributes(), Color.orange);\n   GraphConstants.setOpaque(dgc.getAttributes(),true);\n   graph.getGraphLayoutCache().insert(dgc);\n   ToolTipManager.sharedInstance().registerComponent(graph);\n   graph.addMouseMotionListener(new MouseMotionAdapter(){\n        public void mouseMoved(MouseEvent e){\n            Object o=graph.getFirstCellForLocation(e.getX(), e.getY());\n            if(o!=null){\n                if(o instanceof  DefaultGraphCell)\n                {\n                    //ToolTipManager.sharedInstance().setInitialDelay(0);\n                    graph.setToolTipText("AA");\n                }\n            }\n            }});\n   JFrame frame = new JFrame();\n   frame.setBounds(100, 20, 400,400);\n   JScrollPane js=new JScrollPane(graph);\n   frame.getContentPane().add(js);\n   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);\n   frame.pack();\n   frame.setVisible(true);\n