"Brushing" plots

[fork]

What do other octave users do when you/they want to "brush" plots -- i.e., 
putthe mouse on a point or draw a square around a region and figure
out which points go to a sample ID?

I know you can use "text" with a scatter plot, but it doesn't work 
well with a lot of points.

I managed to export a csv to ggobi pretty easily,
but maybe there is a better way.

Thanks!