Bug 145520 Group name will not show up in group list if the group use default name and key expression has no value
Description: Group name will not show up in group list if key expression has no value. Steps to reproduce: 1. Insert a table into report, bind it to a data set 2. Switch to property editor -> groups 3. Click on add button to open new group dialog, then press ok button Expected result: A new group with default name will be added to group list Actual result: A new group is added to group list, but without group name. But when let group tab lost focus and get focus again, you can see the group name.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
* <code>Translation</code> represents a translated message for a specific
	 * locale.
	 * <p>
	 * 
	 * @param translation
	 *            new entry of <code>Translation</code> that are to be added
	 *            to the module.
	 */
	public void addTranslation( Translation translation )
	{
		translations.add( translation );
	}
	/**
	 * Drops a Translation from the module.
	 * <p>
	 * 
	 * @param translation
	 *            the translation to be dropped from the module.
	 * 
	 * @return <code>true</code> if the report module contains the given
	 *         translation.
	 */
	public boolean dropTranslation( Translation translation )
	{
		return translations.remove( translation );
	}
	/**
	 * Finds a <code>Translation</code> by the message resource key and the
	 * locale.
	 * <p>