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
* 
	 * @see org.eclipse.jface.dialogs.Dialog#cancelPressed()
	 */
	protected final void cancelPressed( )
	{
		
		if ( rootNode.hasSubNodes( ) )
		{
			PropertyNode[] nodes = rootNode.getSubNodes( );
			for ( int n = 0; n < nodes.length; n++ )
			{
				
				if ( !cancelPressed( nodes[n] ) )
				{
					return;
				}
			}
		}
		
		if ( performCancel( ) )
		{
			super.cancelPressed( );
		}
	}
	private final boolean cancelPressed( PropertyNode node )
	{
		if ( node.getPage( ).performCancel( ) )
		{