Any pointers on this?

On Sat, Apr 30, 2011 at 12:34 AM, Soumyaroop Roy <roy.soumyaroop@gmail.com> wrote:
Hi there:

I have an x-y plot and I want to draw a vertical marker (an x=c line) on the plot on a mouse click.

How should I approach it?

regards,
Soumyaroop