Responding to MouseClicks on plots

Hi, 

I have a fairly complex application producing several 2D visad plots. 

I notice that clicking the middle mouse button on the plot prints the
current X,Y values for that point. I want to extend this so that I can
be notified or these x,y values when the user clicks on the plot  and
then perform some additional tasks.

Is there a way to listen for this kind of event?

I have found that DisplayEvents are triggered when the user clicks on
the plot, but these events are only aware of the X,Y coors of the plot,
not the corresponding values.

I would very much appreciate any advice or tips.

Thanks, 
Oliver Mather
Software Engineer, 
omather@xxxxxxxxxx