Bug 140542 label can't be displayed without resource file or unmatched key
Steps to reproduce: 1.New a report, add a lable with text "aaa" 2.Add a resource file for the report, set key to "key1", value to "actuate", apply the value to the label 3.Clear the resource file in Property Editor->General->Resource File (or change the key to "abc") 4.Preview the report Expected result: 1.Display label text "aaa" on preview or 2.Give a warning message to say resource file is not found or unmatched key Actual result: Nothing displays on preview
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
/**
	 * The validation executor. It performs the semantic validation and sends
	 * validation event to listeners.
	 */
	protected ValidationExecutor validationExecutor = new ValidationExecutor(
			this );
	/**
	 * The listener list for validation event.
	 */
	private List validationListeners = null;
	/**
	 * The file name. Null means that the module has not yet been saved to a
	 * file.
	 */
	protected String fileName = null;
	/**
	 * The system id which is needed for resolving relative URIs. It can be a
	 * relative/absolute file directory or a network path such as HTTP, FTP,
	 * etc.
	 */
	protected URL systemId = null;
	/**
	 * The UTF signature.
	 */
	protected String signature = null;
	/**
	 * The default units for the design.
	 */
	protected String units = null;
	/**