title: Programatically Detect window maximization/Minimization??? Eclipse RCP
body: <p>As the title shows, I want to add a listener to my rcp user interface in order to detect maximization and minimization. Actually, it not that my real purpose, but I think it is a way to solve my problem. I have a view with some shapes in the center, and I wonna keep the drawing exactly in the center even if the window is resized. To do so, I used the following listener : </p>
  
  <pre><code>public void createPartControl(final Composite parent) {
      display = parent.getDisplay();
      white= display.getSystemColor(SWT.COLOR_WHITE);
      parent.setLayout(new FillLayout(SWT.VERTICAL));
      final ScrolledComposite sc = new ScrolledComposite(parent, SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
      sc.setExpandHorizontal(true);
      sc.setExpandVertical(true);
      sc.setMinHeight(100);
      sc.setMinWidth(100);
      sc.setSize(565, 305);
      final Composite child = new Composite(sc,SWT.NONE);   
      child.setLayout(new FillLayout());
      // Set child as the scrolled content of the ScrolledComposite
      sc.setContent(child);
      child.setBackground(white);
      gc = new GC(child);
      parent.addListener (SWT.Resize,  new Listener () {
          public void handleEvent (Event e) {
              x = child.getBounds().width/2;
              y = child.getBounds().height/2;
              child.addPaintListener(new PaintListener() {
                  public void paintControl(PaintEvent event) {
                      dessin(gc);  // draw my shapes
      }
      });
  }
  </code></pre>
  
  <p>everything goes well except when I maximize the window and then minimize it, in this case I loose the drawing (it is in the corner).
  Any idea please? I'm I thinking in the right way?</p>