Problem in Painting in JDesktopPane

Question

Hi
Here is the code for my class:
public class DiagramPane extends JDesktopPane{
public DiagramPane() {
setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
public void paint(Graphics g){
super.paint(g);
int cmpCount=getComponentCount();
if(cmpCount>1){
for(int i=0;i<cmpCount-1;i++){
Component cmp1=getComponent(i);
Component cmp2=getComponent(i+1);
g.drawLine(cmp1.getX(),cmp1.getY(),cmp2.getX(),cmp2.getY());
public static void main(String[] s){
JFrame f=new JFrame();
DiagramPane dgrPane= new DiagramPane();
JScrollPane scr=new JScrollPane(dgrPane);
JInternalFrame lst1=new JInternalFrame("Frame1");
JInternalFrame lst2=new JInternalFrame("Frame2");
lst1.setBounds(150,150,100,100);
lst2.setBounds(300,300,100,100);
lst1.show();
lst2.show();
f.getContentPane().add(scr);
dgrPane.add(lst1);
dgrPane.add(lst2);
f.setSize(400,400);
f.show();
Run this code and try to move any of the two InternalFrames. The lines need to be repainted accurately but this doesn't happen. This happens due to background filling of dirty region in JLayeredPane paint method. Can anyone tell me, what I should do so as to make these lines repaint properly. Lines are not in dirty region.
Thanks in advance.
Anil.

Answer 1

You need your own DesktopManager that triggers a repaint after dragging ends, like:
class MyDesktopManager extends DefaultDesktopManager {
public void endDraggingFrame(JComponent comp) {
     super.endDraggingFrame(comp);
     repaint();
then use it in your custom DesktopPane
public DiagramPane() {
setDragMode(JDesktopPane.OUTLINE_DRAG_MODE);
setDesktopManager(new MyDesktopManager());
Greetings
Jeanette