Bug 202891 NPE throws out when click on data item in layout[0001]
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/BindingDialogHelper.java
}
	private void initFilter( )
	{
		if ( binding != null && binding.getFilterExpression( ) != null )
		{
			txtFilter.setText( binding.getFilterExpression( ) );
		}
	}
	private void initFunction( )
	{
		cmbFunction.setItems( getFunctionDisplayNames( ) );
		
		if ( binding == null )
		{
			cmbFunction.select( 0 );
			handleFunctionSelectEvent( );
			return;
		}
		try
		{
			String functionString = getFunctionDisplayName( DataAdapterUtil.adaptModelAggregationType( binding.getAggregateFunction( ) ) );
			int itemIndex = getItemIndex( getFunctionDisplayNames( ),
					functionString );
			cmbFunction.select( itemIndex );
			handleFunctionSelectEvent( );
		}
		catch ( AdapterException e )
		{
			ExceptionHandler.handle( e );
		}