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
/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.core.DesignElement#getSlot(int)
	 */
	public ContainerSlot getSlot( int slot )
	{
		assert slot >= 0 && slot < getSlotCount( );
		return slots[slot];
	}
	/**
	 * Records a semantic error during build and similar batch operations. This
	 * implementation is preliminary.
	 * 
	 * @param ex
	 *            the exception to record
	 */
	public void semanticError( SemanticException ex )
	{
		if ( allExceptions == null )
			allExceptions = new ArrayList( );
		allExceptions.add( ex );
	}
	/**
	 * Returns a list containing all errors during parsing the module file.
	 * 
	 * @return a list containing parsing errors. Each element in the list is
	 *         <code>ErrorDetail</code>.
	 * 
	 * @see ErrorDetail