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
*            The new element to add.
	 */
	public void addElementID( DesignElement element )
	{
		assert idMap != null;
		assert element.getID( ) > 0;
		Long idObj = new Long( element.getID( ) );
		assert !idMap.containsKey( idObj );
		idMap.put( idObj, element );
		
		long id = element.getID( );
		if ( this.elementIDCounter <= id )
		{
			this.elementIDCounter = id + 1;
		}
	}
	/**
	 * Drops an element from the id-to-element map. Does nothing if IDs are not
	 * enabled. Should be called only from the
	 * {@link org.eclipse.birt.report.model.command.ContentCommand ContentCommand}.
	 * 
	 * @param element
	 *            The old element to remove.
	 */
	public void dropElementID( DesignElement element )
	{
		if ( idMap == null )
			return;
		assert element.getID( ) > 0;
		Long idObj = new Long( element.getID( ) );