Bug 390669 [Accessibility]Press 'Tab' doesn't focus on the next report item when adding relative period aggregation.
xtab/org.eclipse.birt.report.item.crosstab.ui/src/org/eclipse/birt/report/item/crosstab/internal/ui/dialogs/CrosstabBindingDialogHelper.java
}
	}
	private static ExpressionButton getExpressionButton( Control control )
	{
		Object button = control.getData( ExpressionButtonUtil.EXPR_BUTTON );
		if ( button instanceof ExpressionButton )
		{
			return ( (ExpressionButton) button );
		}
		return null;
	}
	public static void initExpressionButtonControl( Control control,
			ExpressionHandle value )
	{
		ExpressionButton button = getExpressionButton( control );
		if ( button != null && button.getExpressionHelper( ) != null )
		{
			button.getExpressionHelper( ).setExpressionType( value == null
					|| value.getType( ) == null ? UIUtil.getDefaultScriptType( )
					: (String) value.getType( ) );
			String stringValue = value == null
					|| value.getExpression( ) == null ? "" : (String) value.getExpression( ); 
			button.getExpressionHelper( ).setExpression( stringValue );
			button.refresh( );
		}
	}
	private List<String> getUseLevels( String dimensionName )
	{
		List<String> retValue = new ArrayList<String>( );