render layout bug after upgrade from 2.3.10 to 3.0.5

Hey,

I recently start to upgrade an 2.3.10 app to rails 3, most of the app is
working, at least is booting now.

But there is a problem that I can't understand:

On the application controller from the all controllers inherit I have
this line

layout "default"

on my views I have the file app/views/layouts/default.html.erb

and is not rendering the layout just the action partials.

there is one controller that is working b/c It uses another layout and
the render works like:

render :layout => "homepage"

I try it renaming the layout to application.html.erb no luck either.

I try setting layout with a method on the app controller, for example:

layout :set_default

def set_default
  "application"
end

I try to check what layout is stored on the app controller before
rendering the action with:

logger.info "layout: #{self.send :_layout}"

and the answer is application on the log

I'm out of ideas to solve this.

Any thoughts are appreciated, thanks.