title: updating plot output in shiny r
body: <p>For a Shiny app that I am working on, given a data file, I need to display a barplot (for which I am using ggplot2) on the starting page of the app. So when the user runs the app, and uploads a file, they would immediately get to see the barplot in main panel. </p>
  
  <p>After the app has started, the user should be able to click an actionButton to bootstrap the data and add error bars to the same barplot. I don't want to add the error bars to start with, because my users might not be interested in the error bars and adding error bars with bootstrapping would keep them waiting. So, I must add the error bars only if they want to see it and are willing to wait for bootstrapping to be over. </p>
  
  <p>I tried many ways to update the plot but haven't been successful. I could of course render another plot with the error bars but it is not what I would like to do ideally. Is there a way to update plots or add features to them?</p>