Bug 134988 [regression]Available items in Query didn't change when change data source in Edit Data Set Dialog.
Description: Available items in Query didn't change when change data source in Edit Data Set Dialog. Steps to reproduce: 1. New two different data sources. 2. New a dataset, change data source, view Available Items in Query pane. Expected result: Available Items in Query pane changed according to new Data source. Actual result: Available Items in Query pane kept unchanged.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/data/ui/property/AbstractPropertyDialog.java
* @param parentShell
	 *            The parent shell
	 * @param model
	 *            The model object that the dialog pages will interact with.
	 */
	public AbstractPropertyDialog( Shell parentShell, Object model )
	{
		super( parentShell, "" ); 
		setModel( model );
		setShellStyle( getShellStyle( ) | SWT.RESIZE | SWT.MAX );
		propertyPaneLayout = new StackLayout( );
		rootNode = new PropertyNode(
				"org.eclipse.birt.report.designer.ui.dialogs.properties.propertydialog.rootnode" ); 
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.designer.ui.IPropertyPageContainer#setModel(java.lang.Object)
	 */
	public void setModel( Object model )
	{
		modelObject = model;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.designer.ui.IPropertyPageContainer#getModel()
	 */
	public final Object getModel( )
	{