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
assert idMap.containsKey( idObj );
		idMap.remove( idObj );
	}
	/**
	 * Looks up an element given an element ID. Returns null if no element
	 * exists with the given ID. Also returns null if IDs are not enabled. Note:
	 * this method will not find an element that has previously been deleted
	 * from the module, even if that element still exists in memory in
	 * anticipation of issuing an undo of the delete. That is, only valid
	 * elements can be found.
	 * 
	 * @param id
	 *            The id of the element to find.
	 * @return The element itself, or null if the element can't be found or if
	 *         IDs are not enabled.
	 */
	public DesignElement getElementByID( long id )
	{
		if ( idMap == null )
			return null;
		return (DesignElement) idMap.get( new Long( id ) );
	}
	/**
	 * Returns the undo/redo stack for this module.
	 * 
	 * @return The "command" stack.
	 */
	public ActivityStack getActivityStack( )
	{
		return activityStack;