title: gWidgets return multiple responses for multiple columns
body: <p>I posted before on this and was not able to arrive at a solution with the single posted response.  I have tried another approach that gets me what I want, mostly.  The current solution would work better if it were in a single dialogue box but I am not sure how to do this.  I am putting together other solutions I found on Nabble and stack and just cannot get what I need.  I want the following to offer the choices in a single window, instead of having the user input into 3 separate boxes.  Please help.</p>
  
  <pre><code>options(guiToolkit="RGtk2")
  library(gWidgets)
  #Creat selection function
  select &lt;- function(x,multiple = TRUE, Title,...){
    ans&lt;-new.env()
  
    x1&lt;-ggroup(horizontal=TRUE) # no parent container here
    x2&lt;-gcheckboxgroup( x,multiple=multiple,con=x1,expand=TRUE)
    ret &lt;- gbasicdialog(title = Title, widget=x1,handler=function(h,...){
      value &lt;- svalue(x2)
      if (length(value)==0) value=""
      assign("selected",value,env=h$action$env)
      dispose(x1)
    },action=list(env=ans))
    ans
  }   
  #Create list to store results
  Days. &lt;- c("Day1","Day2","Day3")
  Outputs_ &lt;- list()
  SelectionOptions. &lt;- c("Bicycle Event1", "Construction Nearby","Path Closure")
  
  #Cycle through each day 
  for(day in Days.){      
      ans &lt;- select(SelectionOptions., Title = day)
      Outputs_[[day]] &lt;- ans$selected
  }
  #return results of selection
  unlist(Outputs_)
  </code></pre>