Given code like:
class FooController < ApplicationController
  # The intention here is to detect any problems with the requested URL before
  # it is loaded in an iframe (see FooController#preview).
  def preview_init
    # work... 
  end
  # This fetches a remote page and prepares it for viewing in an iframe.
  def preview
    # work...
  end
end
The outputting documentation for default_init will indeed link to FooController#preview, but clicking it merely expands the source for preview_init.
It seems that the click handler needs to check to see if the event.target is actually a link, in which case it should not do anything, and allow the default action to proceed.