title: How to split SASH from in SWT?
body: <p>I created an application with two parts :</p>
  
  <pre><code>      1. tree viewer
        2. table viewer + messages
  </code></pre>
  
  <p>it look like</p>
  
  <pre><code>                 -------------------------------
                   -   tree    -         table   -   
                   -           -                 -
                   -           - -----------------             
                   -           -    messages             
                   -------------------------------
  </code></pre>
  
  <p>I tried to build Sash from thaty will split the tree area and the table + message area.
  Then I want to split the table area to two area table and messages.</p>
  
  <p>I got error message when I tried to do the second split of table and message.</p>
  
  <p>This is the code</p>
  
  <pre><code>  SashForm sashForm = new SashForm(parent, SWT.HORIZONTAL);
      Composite treeComposite = new Composite(sashForm, SWT.BORDER);
      Composite detailsCompositePart = new Composite(sashForm, SWT.BORDER);
  
      GridLayout parentSideGridLayout = new GridLayout();
      parentSideGridLayout.numColumns = 1;
      detailsCompositePart.setLayout(parentSideGridLayout);
  
      sashForm.setWeights(new int[] { 300, 700 });
      createTreePart(treeComposite )
  
      SashForm verticalForm = new SashForm(detailsCompositePart, SWT.VERTICAL);
      verticalForm.setWeights(new int[] { 800, 200 });
  
      detailsComposite = new Composite(sashForm, SWT.BORDER);
                  createDeatilsPart(detailsComposite )
      messageComposite = new Composite(sashForm, SWT.NONE);
               createMessagePart(messageComposite )
  </code></pre>
  
  <p>I got error message after this statment</p>
  
  <pre><code>        verticalForm.setWeights(new int[] { 800, 200 });
  </code></pre>
  
  <p>"Argument not valid" when i tried to do the second shash
  Could you advise me How i can fix this issue ? </p>