Bug 153378 [Regression]Label text won't show up when the text key is not found
Steps to reproduce: 1.Add a label, set text to "aaa" 2.Add a resource file "a" to the report, add a text key "k1" which is not in the a.properties to the label 3.Preview in Web Viewer Expected result: Label display "aaa" when the text key is not found Actual result: Nothing in preview
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/util/DocumentUtil.java
assert targetDesign != null && target != null && source != null;
		assert target instanceof SimpleDataSet;
		assert source instanceof SimpleDataSet;
		Module sourceModule = source.getRoot( );
		assert sourceModule != null;
		DesignElement dataSource = source.getReferenceProperty( sourceModule,
				SimpleDataSet.DATA_SOURCE_PROP );
		
		if ( dataSource != null && sourceDesign != dataSource.getRoot( ) )
		{
			DesignElement copied = ModelUtil.getCopy( dataSource );
			addElement( targetDesign, copied, ReportDesign.DATA_SOURCE_SLOT );
			target.setProperty( SimpleDataSet.DATA_SOURCE_PROP,
					new ElementRefValue( null, copied ) );
			
			resolveElementReference( targetDesign, sourceDesign, copied,
					dataSource );
		}
	}
	/**
	 * Resolves data set reference in the target element. This method will copy
	 * the resolved element reference from the source element to the target
	 * design.
	 * 
	 * @param targetDesign
	 *            the target design to add the copied data set
	 * @param sourceDesign
	 *            the source design from which to get the copy
	 * @param target
	 *            the target element to resolve the data set