Bug 119331 Library - name space terminology and behavior
During BIRT 2.0 library feature review meeting the following change was decided. - Change the term namespace to 'prefix' - By default use the library name as the prefix ( namespace ); the dialog to input prefix should be prompted only if hte auto generated prefix is not unique.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DNDUtil.java
return getObjectLength( ( (StructuredSelection) obj ).toArray( ) );
		}
		else if ( obj instanceof Object[] )
		{
			return ( (Object[]) obj ).length;
		}
		return 1;
	}
	/**
	 * Checks whether child's container exists in handle array
	 * 
	 * @param content
	 *            child handle
	 * @param handles
	 *            handle array
	 * @return if exists
	 */
	public static boolean checkContainerExists( Object content, Object[] handles )
	{
		content = unwrapToModel( content );
		DesignElementHandle child = null;
		if ( content instanceof SlotHandle )
		{
			child = ( (SlotHandle) content ).getElementHandle( );
		}
		else if ( content instanceof DesignElementHandle )
		{
			child = (DesignElementHandle) content;
		}
		if ( child != null )