[R] Interactively editing point labels in a graph

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Dear experts,
I would like to be able to interactively (if possible, with mouse and clik) edit point labels in graphs, particularly in multivariate graphs, such as the biplots you get after a correspondence analysis (with, for example, package ca), where labels tend to overlap. The graph aspect ratio is relevant (it needs to be mantained). And I'm working with Windows XP.
In this kind of graphs points in the graph are identified with labels, generally long (see, for example: http://www.white-history.com/Greece_files/hlafreq.jpg), and sometimes -as in the example- it is good to group certain points within ellipses.
Do you know if exists some package able to do this task?
Thanks in advance,
Hug