I have the following code snippet on the documents#index view page of
my rails app.

<%= periodically_call_remote(
  :url => {:controller => 'documents', :action => 'index'},
  :update => 'documents',
  :method => 'get' )
%>

The page shows a table of document records.  Since these records can
be updated asynchronously by a message broker feed, I want the above
code to activate every 10 seconds (the default) and refresh the page.

Now, the page has a sidebar and when the time ticks the first time, I
get a complete copy of the entire page, including the sidebar,
inserted into the main table section of the page.  I think the problem
is in specifying the :update => 'documents' div, but I just don't get
how to scope the region to be updated.

I can supply more info, such as the layout page and so forth, just ask.