Bug 136256 Enhance the message builder
Please see the spec attached in 133995 for detail.
UI/org.eclipse.birt.report.designer.ui.lib.explorer/src/org/eclipse/birt/report/designer/ui/lib/explorer/LibraryExplorerContextMenuProvider.java
menu.add( addAction );
			}
			IAction removeLibraryAction = new RemoveLibraryAction( treeViewer );
			if ( removeLibraryAction.isEnabled( ) )
			{
				menu.add( removeLibraryAction );
			}
			menu.add( new Separator( ) );
			IAction refreshAction = new RefreshLibExplorerAction( treeViewer );
			if ( refreshAction.isEnabled( ) )
			{
				menu.add( refreshAction );
			}
		}
	}
	private LibraryHandle getSelectedLibrary( )
	{
		ISelectionProvider struViewer = (ISelectionProvider) getViewer( );
		IStructuredSelection selection = (IStructuredSelection) struViewer.getSelection( );
		if ( selection != null )
		{
			if ( selection.getFirstElement( ) instanceof LibraryHandle )
			{
				return (LibraryHandle) selection.getFirstElement( );
			}
		}
		return null;
	}
}